e_ ËFuptg oF solß RAI{EÏ I{ICrcI,

C,AIAITZqD .SEACYIIOI{S.

ô', thoslc prssentodl for tho Dognoc of

Dootor of PhIloso¡ù5r

1n

tho U¡riversitY of Acl'el¿iclc

by

Keith O1iver ltrfacLe, B.So.

Department of Organio Ohenistry

Decenbor, 1!66 c0Nrßt¡Is

Paqe

Suunary: (r)

Statement: \ 1'r'1.,

Aclgrorleclgenentsi (1")

Introcluotion¡ I

Chapter It Hyd,nogenolysis of Group l\b-ofgano oom¡nundso

Disoussion 21

Ex¡rerinental ¿É

Chaptor IIr IIhe aotion of Raney niclcel on ar¡iline ancl relatecl com¡nund,s.

Disoussion 61

ts:çeri.nental. 96

Ghapter lflr S¡rnthesis of monosubstitutect 2 e?r -biprynicl¡rls. Drisoussion 115

B:c¡rerimentaJ. 126

Appendix; No¡nenol¿tu¡e of organosilicon aompounds: 137

References¡ 1t8

IJ; (i)

SUM¡TA.RT

Thi.s stu{y of the ¡rectranisns anil synthetio applioations of organío æactions rith Raney nickel catal¡rsts has been divid'ed' into th¡se sectÍons; the irvestigation of the cleavage of Onoup I\l/b-organo oonpor.rncùs with Raney nicket, the exanrinatlon of the alþrlation of anines aata-ì¡rzect by Baney n5.ckel, and, the synthesis of geve¡¡al 2r}r-b|pyriqyl derivatives"

1,welve pürer¡.yl dlerivatives of silicon have been cleavecl by treatment with several Raney niokel catalysts to give nixtuæs of benzerp and. oyclohexåne and. small quantities of by-produots i.noludlng bipheryl and. tetracyolohe:rylsiLanee lletr.aphepylstar¡n¿ne , tetra¡ùrer¡ylgemøne , triphenylgermanol, and. tetraoyclohexylplr¡¡¡ibane were similar\r cleaved.t rùriLe aIIqrI d.erivatives of silicon and. tin wore for¡rcl to be stable under ¡¡re conðitior¡s r¡sed,o Phenylsubstitutecl siloxanos ard Eilanols vers losa read.i\r split tha¡¡ those silanes rrithout orçfgen fi¡nctions. A mectrar¡'ism for the cleavage of organosilicon bond.s has been p:roposed', involvJng ohenisorption of the silioon atom by aacepting electrons into its empt¡r 3$ orbltafs, expulsion of a pher5rl anion, a¡d. lSrdrcgenoþsås of the remainlng groupso this reohanísm has been discussed rLth res¡nct to otl¡er Group lllb-organo derivatines. The :seaotions of anili¡re and. cycJ"ohoçylanine with Raney nickel

giving !-oyolohelylanjJ.ine ard. othor relatecl seoond.ary anines has been stud.ied,n 1lhese reactions have been extend.ecl ¡s 4-f¡apht]lyla'mine, the toluiclines, af¡d om¡nuncls rith twp nitrogen at+îs, irrluÉtirlg J-awinoF (ii) pyrièine, J-anínopiperidine, 1r2-ùia.uui:roayclohexane, and. the pherylene dia¡¡.ines. The æactiong have boen shorn to be a usefirl synthetie ¡nthlay to N-a1kylaryIamineso The ¡æaction pathnrays and. necha¡¡is¡ns of these roaotions a¡¡o d:iscussed. with respeot to the types of ad.sorptions possíb1e between nitrogen and. Raney nickelo [he ¡¡esLûts of pnevious workers has been oorrelatecl. by these conclusions.

lii ghteen neu l+-substítutecl 2 12' -blpyriclyls øo:ñ. 2 r2r -bipyri4yl¡' î-oxides have been s¡mthesiz"å.'r"or 2:.;2¡-bípyri{y1 by a synthetío :¡outo

I thnougþ Þnitro-Z ¡2 -b ipyricl¡rl-î -oxiôe r

arl'' (ru)

STAîE.},ßMT

clesoribecL in ttrio tt¡esis incorlorates llhe woik - no naterial prevÍousþ subnittect for ar¡y clegnee in ar¡y University, ar¡d, to the best of qy Imowlecl'ge and' belíef oontains no materd.al previously publtsl¡ed' or rr¡dtten by another Person exoept wtrere due reference ls nad,e in the text¡

Keith 011ver Ï[a'ðe. IDeceribor, 1966. (¿")

ACKNOVILEDGСíE¡¡TS

I einoet¡elJ thar¡k Dr. IÍ.H.F. Sasse for the inoepbion of thi.s prrcjeot a¡rd for his enthr¡síastio guid.ance and. help througþout the worko lhanks also go to Dro {LD. IVa¡rl ancl Dro Ri.A' Jones for their assistance and. contribution of jdeas.to later stages of this prcjeot'

I gratefulþ aoknonrl'ed.ge Dr. 1l'o Mc[.,. Spotswood' for helpfr¡I cliscussions on nuclear ragnetio resonance speotra, Dro JoH. Bomie for assistance with intelpf€r tation of mass speotra, a¡¡d. Dr. K. No¡rish, Division of soils, c.s.I.R.o.¡ for silicon dete¡xrinations.

I aJn cleep\r j'rrd,ebted' to Ihe Urr.iversity of Ad'e]"aid.e for the a1100ation of a trÙosearch Grant for the dr¡ration of this rcrko

}JJ -1*

II{IRODUCIION

Catalysis is one of the firr¡da¡nental pr€cesses of organic cheuistzy, antt incLeecl it nay be cor¡sicLeneil t]¡at near\r all reaotions ir¡volve some kind, of oatal¡rtic effeot. Cbenioal oatalysts, bottr homogeneous and' heterogeneou¡¡, are clefined. as species wt¡icb by forrni¡g a.r¡ intermeðiate complex w'ith a compog¡d. gncLergoing reaotion lov¡er the aotination enerry for the reaotion ar,ld. conseqr:entþ i-ncrease the reaotion rate. Perhaps tlre most intriguing of these ane the so]jicl heterogeneous r¡etal catalysts, for the nature of, their su¡face properbies and, their nod'o of aotion is prcbab\r the teast understooil of al.l catalystso Arottg the most w:iitely hrg1rn of these metal catalysts is Raney niokel, first ðeveloped. i^ 1gZ7 by trúurray R"ooyl by leachir¡g aLluini,,'r from a ,¿s¡st-alu¡nlniruo a1loy with concentrated. sod.ír:rn, tSrtl'roxide solu- tiono The resulting nickel'{ras in a higþþ aotive fineþ clivid'eiL forn incozpor."ating a oonsiderable qr.rantity of the þclrcgen d'erived' from the aotion of, soclfu.m lgrcLroxicte on alr¡ninir¡n. åidkins a¡ld. hls codworkersz'Lt5 were ¡esponsible for a consld.erable d.evelopment of thj-s catalyst" By vard.ations of the d.igeetive ancl washing pr"oc'eclures, the tlyd.rogen sontent of Raney niakel .¡vas increased., uraking tl¡e oataLyst more aotive tovrard.s þitrcgenation ¡reactions. The fi¡st nod-lfiaatie¡¡ f,as termeil by Adkins as Iy-| Ra¡ey niokel2 ar¡cl the seoor¡d. rùrlch was nade by Mozingoz as lÍ-2 Raney niakelo Srrbsequont oata\rsts d,evelopett by å'cttcins anct

assooiatoct worlcors wero nanedt It*Jr W-trrb ¿¡¿ g-!rYf4r a¡¡d' W-/ i', o¡¡ôer -2-

of increasing aotivity. More recentþ, ctegassed' oatalysts suctr as It-p trilaney niolcel developed. by Sasse6 L¡ave been irwestigatecl and. for¡nct to have quite Bpecific properties. f,he preparation of Tf-Ë catalysts l¡rvolve the heating of, T[-J Raney niokel r¡¡rder reduced pressu:re at tem¡rratures uÉtuÊllJ between 100 ar¡ct 2@o, thus removing a consid'erablo portion of tgrd.rcgen. The ¡¡eaotions on this oatalyst wi-L1 be consid'e:rod' in nore d,etail later. This large variation in the lqrd.nogen content of Raney nickel makes it perhaps üxe most versatile of al1. metal oatalJrstsoT Besides a great nu¡¡ber of lgrihrogenation and. tgrilrogero\rsis æaotions, Raney nickel has been used' for a variéty of other reactions rerrich have been a¡npLy reri¡iewed' by other *o"k"""o8 Howener, despite a pr^oI1fio flow of work publisheil on the reaetions of Raney nickel cataþsis, oomparativeJ"y littl'e is Imonn of its st¡ructureo o RaneyT first suggested. that the catalyst is a xrixtu¡e of nickel

anð' proposed' that \ycLrid.es incltrd.ing NjHZo Later EreiclLin V.ilolnt "lO the þd.rogen 1s partly acLsorbe¿l on the ¡rj.ckel surface ar¡d. the rest 7 clissolvecL in ttre bulk nickelo SmithrChsilwell and' Kirs].i.s showed that the aotivity of Raney niokel is cti¡reet\r proportional to the tgrd'rogen content, and. conch¡d.etl that the gas was held' to the niokel in sone

unspeoified. metastable ,state and. was ¡¡eleased. as ÏSrd.rogen atomso Hott¡- ever, no theoretical or practÍoal ør¡id.e¡ss was prod.uced. for these postulates, anil j.t was not r¡ntil 1959 whenKokes and' 8¡n¡netrll'|z p,rb- Ils¡ect æsults of a thoroWlr phystoal iunestigation, that an¡r reaL -3- insfdht into the natuze of the oatalyst uøs obtai:red.

Kokes a¡rcL Erunett calculatecL from cl.ensíty neasurements that TrI'6

Raney niokeL contaj¡ts apprcximateþ 5VÁ l¿ttice d'efects Ín j-ts crysta1 stnrotuæo Assu¡ring that eaoh lattice r¡acancy ¡etai¡s ono t5rd.ægen atom, a tgrd,rogen content of 70 nû,ig of cata*lyst may be esti.mated, a figune wtrich ls close to the measure¿l value of 72-81 nlr/g"

Magnetio rneasu¡¡emer,t"ll shoTYed. that råf-6 Raney nickel has a low magnetic susceptibility rvtrich rises proþorbional\y as the oatalyst is d.egassed.e Prom this evid.ence, Kokes ard. Emmett cor¡c1ud'ed' that ttre last two eleotrons ir¡ thu g band. of nickel must be useil in boncli-ng to lSrd'mgen atous, æô ane ¡released on ¡emoval of lSrd'rtgen Differential ttre¡mal ana\rsis, X-ray d.iffraotion, and. surface area stu¿ies also nrle out tlre possiblllty of the furcl.mgen being ¡ù5rsioal\y adsorbecl or in solution rrith nickel. In conc¡¡sion, Kokes and. T:mmett suggestecl that Raney niclcel is a sr¡bstitutlonal alloy of Ì5rôrcgen and n-iokeI, in which approximaþely 3Ø of the lattice sites in the face-centrecl cubio crystal stnrotu¡re have a hyd.rrcgen atom replacing a nickel atoni the Ï¡rd.rcgen is helcl by oor¡al-ent bond,ing tlrrougþ ttte 4 bancl eLeotrons of nj.okelo Thi-s lSrd'nogen may be neuroved. by degassing at hígþ temperatules, Ieaving the nickel lattice stmotuæ nost\f unctrangecl. and, presr.unabþ held' Ín place by the snall quantities of resichral ah¡ntr¡a in the oatalyst. These lattice vaoancieg nay rlso be reoccupiecL at higþ tem¡nratu¡es antl pressure by lSrd'rogen or

some other organlc nolecr¡le uflich oan bond. (or chemisorb) to the nickel

in a sinilar ma¡¡nsr. qlr

Irittle is lsrown of the exaot natuæ of this bond'ing or cheni- sorption of orgauio compounds to netal oatal¡rsts, and Partly beoausc of this, much is still ur¡lmown about ¡neohanisms of metal cataþsis. In o¡d.er to lea¡n mo¡re about these meohar¡isrns, seneral author"s have stucllect the poisoning of metal cataþsts w:ith varÍou^s agents"

Ua¡cte¿1, stud.iecl systematical\r the poisoni-ng of the Group VIII metal eata\rsts, niokel, pallad.i.umrancL platinr¡no He d.efinefl a poison

as a compor¡nd. rvhictr by foruring strong chemioaL bond.s to the metal and'

nemaining in this bou¡rd. state for a greater propoÉion of the reaction

tjJno, red.ucecl the nu¡¡ber of oatalybio sites available for reaotiont

and, tlividecl these into three grouPsolh

(") Organio der{vatives of Gr.oups V, VI, and. VII. which aot as poisone shown that by ctremisozption JËi3 a lone-paÍr of eleotror¡s. Ma¡cted' has rrpnotectiorlr of these lone-¡nir electrons by prctonation or oxid'ation great\r neduces ttre toxic effect, as in the byctnogenation of pyricline (1) g¿g the pyricuni.un ion (ta) to plperi¿ine (A).

+ H^

(r) toxio non-toxio

Maxtecl d.ict not obse¡¡/e an¡f poÍsoning througþ olrygen lone-Palrs, but this has sinoe been neporbedl5 althougþ it ocouæ to a lesser degreo. -5-

lhis poisoning by means of heteno-atoms is very irnportant as tt¡e basis of a larç series of cataþtio reactions co¡¡nnorù¡r known as Ì5rd'rogeæ olysiso the best known exauple of these is the d.esrrlphuri'zal'l;on:¡eaction whioh has been e:çJ.o:recl ard. applieil in consid.erable cletail over the past 16 twonty year'so '17 '1I

(¡) Derivatives of metals ín which all- five ozbitals of a ¡! shell Lmmecliate\r preoed.ing the s ar¡d. ¡ valency shell,s are nearly or conpletely fil'ted nay poison retal c"ta1ystsol9 Poisoning by suctr compound's is claj-mecl to irrvolve d.onation of a pair of eleot¡^or¡s from the ¡[ shell of the poison to the oatalysto Setramett¡rJ.plunbane, for exampl'e, has the eleotrcnio oonfÍguration -

,t Pb 1t 1¿ îù ll fú I I I 59

Maxteti suggesteð that it is chenisorbecl to a nacar¡t orbit¿rl in ttre oatalyst by ctonation of two eleotrong from the penultí-nate 5$ shell of

1ead."

(o) Compounds 1hich can be chemisolbeil by bond'ing thnougþ the a1- electron cloud. of a rrultiple bond, may also act as poisons. In nan¡r oas65 this leacLs to lgrilrcgenation of the mrrltiple bondo lxlle strrengttr of 'chenisorption bonds has been estinated' for nan¡r d.ifferent systems by measuærnent of heat of ad,sorptionr'O'21.and. it is

the st¡rength of this bord nhioh clete¡mines the r¡Iti'nate ¡nth of the -6-

*aotion.22 T¡hile ail.sorbect to the catalyst, the reacting s¡ncies rxrclergoes further reaction s¡¡oh as rearnangement or ad.cLition of t5rclægen¡ follonrecl by d.esorption of the prod'uct.

. Bacl.ger an¿ Sasse2S lt^u. appliecl. Ma:cted.l e theories to the fo¡uatíon of 2r1t-bipyridyl (5) from Byrid.ine over IÍ-p Raney niokeln lhey postr:ilated, a rpohar¡ism involving the ctrenisorption of pyrictine by donation of the nitrogen lone-lnir to nlckel follo'¡red' by ad'clition of a valence in þËlrogen to ttre nitnogen atom, forning a railical with free t^Ìre ø-positiono When two of these species come close enougþ, tbey ooar bj^ne, and. on d.esorytion aryl delSrclrogenation gíve 2r2r -biPyriclyl" the view of Kokes ar¡d' Ernnetf otou""", tr[a':cted'r s theory In " "'o"kr11 beoomes inad.equate. the assr.urption tbat ttre originaL bor¡d'ing to the oatalyst is by d.onation of a lone-pai¡. of electrons from the nitrogen atom means that the meohanism lnvolves ttre acld.ition of a t\yd.rogen rad.ieal befo¡r clLnerization ard d.et5nùr.ogenation oarr occuro25 It has been observed ttrat the aotion of d.egassed. Raney nícke} on pyrid,ine gives far better ylel,fls of 2r2t-bipyridyl than an r:ndegassed' If-7 Raney nickel, and calcr¡- l and. s rrorkl that not enougþ þd'rcgen lations from Kokes Ennettr "ho* exists in ctegassecl. cataþsts for this mechar¡ism to operate. j¡rvolve f,o postrrlate a mechar¡is¡n then, ít appears necessaly to a d,onation of electrcns from the metal to the substrate. rvhioh sr.ùsequent\r

d.oes not requine the acldition of tgrdrcgen (Scrrøue l)'2]* lhis nay e¡æ1ain w\y clegassed. catalysts which.alæad¡r have mons vaca¡¡t sites ¡nr pnit oell for adso4ption, give better yielcls of biaryl -7-

.--> H I o N Ni- i Q Ni Ni- I

E H N + \ Ni-

þ)

Scheme I o

24 than tgrclnogen rich catalystso to Ehe iclea that eleotrons can be d.onatecL f:¡om the catalyst nitrggen is not wlthout fuzther ana1ory. Itrahba and' Ker¡baLL25 h^ve tungsten' stuòiecl the heats of ad.sorption of anroonia to the su¡face of ironr a¡¡cl'nlokel. lhese authors have proposed a neclranism whiotr lr¡volves electrons f¡ron the retal in the cheuisorption bond'

H-NIf $ óo 2 + I i, M-M M M

The transient partici¡ntion of the leae-pair on tbe nitrogen is found. to be supportecl by the fast that the pnotonated slnoiest Iüf.+ is nonrtoxie (i.e. not ad'sorbecl) to oatalytt"o26 -8-

How the metallic eleot¡rons of, the g bar¡d. aetually Parbicipate in bond.i¡g to ttre ad.sotbate is open to debateo It is weII }cnown that oatalytic aotivi.ty of metals is conflræd. to the tra¡rsition series which have ínconplete\r fillect d. sheIIs. lhe most aotive retals tor'vard's oatalysis, for examplle, are niclcel, pallaci.ir¡m, and' platinr:m witùr 8$ eleotrons i¡¡ their valencÐf shell. Howener, the nechanis¡o of ctremi- sdrption cannot be expLained. enti¡rely by considering onlJr aonation of these d. ]'eveI eleotrons to tÌre bond" to und.ersta¡rcl the r¡ature of these bond.s, it 1s neoessary to firgt uÞta.l consider some aspects of the theory of sol'íd, stateo Isolated' atoms have their d. electrcns in separate d.iscrete energr levels wlrich' on fo¡nation of arystal stn¡sbu:¡es; broad.en out to a d. band' of electrons with a wid.e range Í.n enorry stateso faufi.ng2T has PostUlatecl' that these eLectrons of the ¡| band. in crystals nay be of tl¡æe typs: boncl'ing (in ttre forrn of, dgq Wbrids), atonic (or non-bond.ing) and' ¡netallic (associated, with conduotivíty). Since the first of these are elready these are bor.¡nd. up in metal-metal linkages, lt is very unlikely that a of the used. in cheur:isorption, for such a borrd. would. cause break-uP oataþstr s crystal st¡ßrctulPo 0onsequentLy, either the atonio or metallfc eleotrcn"g nust be *u¿ rn boncilnge Magnetio anÅ conductivity both clata of cata\rsts rith ad.sorbed. ]Srclnogen, nitrogen, ancl o:rygen ,indicate that it is the atomio (norrbon¿lng) .g orbftal eleot¡¡ons rvhich a¡¡e ir¡volved. i.n chemisorption.2S -9-

If the higþest occupied. level of the metal lies above the higþest ocoupied. l-evel of the aclsorbate, then an exothenrio excha¿ge of electrons from the oatalyst to the ad.sorÈate is possibleo Hovrever, it has also been shown that in the above cases of adsorption, surface d'ipoles ane almost non-exist uot r29 precr'ding the possibility of d'ative bond.ing and. sqggesting very strongþ a covalent cheni.sorption. Hence, it is the energr levels of the bond.ing electroas in the ad- so¡ùate whict¡ d.ete¡ml¡re the clegnee of dative boncling, and this rrlti'nately controls the path of the reactiond Caution is need.ed' in applying thi'e theory, however, as the above conch¡sions have been clrawn fron the stu{y of aclsorbed. gases on metals, but si-mllar eleotror¡lo principles rnigþt be expeotecl to app\y to ¡eaotions in solution. In an extension of the work on the fo¡mation of 2r2t -bLpyridyl fron pyri.d.ine, S""""'0 has irwestigated. the ¡reactions of qui-noline (4) over d.egassed. Baney nickelo The reactions YÍe¡¡e found' to be smewhat d'ifferent, giving, besid.es a much snaller yielcl of the analogous Zr}t-bj:aryf (tO)t a serd.es of eigbt other compoturds (Scfeme Z)o 1lhe fornation of these products nay be explainecl by considering the ct¡er¡isorption of the two (L) onto the compor:ncls ,1r2r3rÞtetmsrd.roquinolf"" (5) and' quinolfue n¿.koloJo lhe forr¡ation of 2r2r'.biqu.inofyf (f O) was very 1ikel'y to be id.entie¿I to the formation af 2r2t åipyri{y1 from pyricline, the lorver yield.s oar¡sed by sterio fuoto*.25 fhe ø"nettSrlation giving 2-neth)¡I- quinoline (1t) iras been stuclied by Meyer\r ar¡cllfieinburgrll and. it nay be

asstted. that a sj-mil'ar meohanism will operate here' Thjs ø'netÌ5r]'ation ,, _i O. ffi3

-+ N N H H (tt) (r z)

H

N a I (¡) H (¿) Ni

NIf 2 + (ffi2)* N 3 (ro) (z) (6) + I 2 t N (tr) H

(8) (g)

Sicheme 2. of, nitrogen heterooyclic coupour¡d.s has been !¡rorr¡ for some tit".51 '32'31 Eomation of the. other products,- in padicular, indole (12), l-tetfryf- haole (15) and. oa¡baz.ole (g) been irwestigated, closely by J""k onr']4 wbo stucLled, the reaotior¡s of T r}rJrlrtetratryclroquinofino over Tf-Ë 8à¡ley nÍol¡o1" -11-

infloLe, Jackson S"s"uJ5 trn their stud¡r of the fonration of "rrd' have i¡rvest lgatecl the ¡¡eactions of s eve ral N-alþI-g-a1þlanilines with lT-Ë Raney niokel, in which the possible products from cl-eavage of the i-2(f4) , Z-r(l5)rand. ,-4(16) bonds of tetraÌgrd.roguinoli:re weæ inclt¡d,edlo

H (t¿r); B H, Rr ¡ rPr N\ = R (tùt R = Me, Rr ¡Et R (t6); R = rit¡ Rl eMe

Àlthougþ none fittecl exactly the results obtained from the quino' line :reaction with negard, to ind.ole fornnation, these authors conclt'¡d'ed' that !-nettry3.-g-etþrlanil,ine (t5) fitted. the resu-tts obtaijreil from quinoline better than the othersr arid. proposeËl that tetratSrcl'roquinoline is cleavecl prefeæntialþ at tl¡e 2-5 bonclo This cor¡fimecL the earlier uork of Pad.oa36,57 n* stud.ie¿l the þd.rogenolysis of qui.raoline anil lr|rSrt+-tetratgrdzoquinoli-ns (5) q¡er ¡¡ed.ucecl nickel oata\rsts at' z60-

2BOo. Pacloa conoh¡ded. that tetraùyd.roquinoline cleaved. througþ t]ne 2-1 bond. ancl recyalized. to give J-methJrlind.ofe (t5). However, his work on qui-noline in which he claj-med. to obtain 2-netþrlind.ole has been ques- r35 apparr:nt1y obtaj-necl a nixture of J-methrLindole tioneð.r'o ^* he has and. i¡d.ol'e, as obtaineil by S"""e.JO ¡u.oLuool4 has also stu¿l1ed. the reaotion of tetralrydroquinoline

(¡) orrer rtl-p Raney nickel, anil slmil,arly has obtainecl a proportionalþ h Iarçr y#fa of J-rnetkgrllr¡clo1e besid.es a number of þd.rogenateil prcd'uctst 2rlr-biquinolyl ancL other prod,rrots as neporbed from qu.inotine. lte -12- prioposeil ttrat N-mettgrl-o-etl¡ylanili¡re (lS) t fo:::ned. by cleavage of tetrah¡rclroqulnoline, B¡ay necyclize to j-methrIfurdoIe (tÐ, or unôergo stepwise d.egraclation of the sid.e-chains to give pol¡mrethyfene (7) a¡r¿ other amineso No $-netl¡yI prod.r:cts Ìvere ísoIated., but g-s¡hylarrÍjline (8) cou.l-d. cycLize to Írrd.oLe (lZ) , ar¡d. both g-toluictine (6) and. a¡rifine we¡re d.etecte¿L in small yield.s"

Jaokson and. SasseJB obtairred. evidence for at least four ¡nth'nays for the fo¡mation of oa¡bazofe (9) from an:ili¡e with Raney nickel oatalysts (Sofrene ¡). Ä11 thæe Ínte¡med'iates, 2r2r-d'íaninobiphenyl

(tz)

2 -+

H NiI 2 (r e) (g)

H

(1e)

Scheme l" -15-

(,tù r 2-aarinobÍphetyf (18), and. diphergrlanrin" (lg) uere isolatod' from the reaotion of a¡ritine with Yt-ä Raney nickel, and a].l' r¡uere found' to give oarb azoLe i.n various yield.s r¡nd.er si¡rilar cond'itions .38t39 the cyclod.eÌgrd.nogenation of di¡ùrer¡rlas¡ine lo caùazoIe has been knorvn for some ti.mer md has been shown to occur catalytic"Uyr4o, pyroþtioaUþ]"¿ arrti photoctrenicall¡r .43 J+4'45 The proposeå ¡necharîisn for ttre cyclizatj-on j.s of diphergrlaurine and. for tfre formation of 2r2t-díæínobiphenyl (17) (Zl).'8 essentiql'ty the sa.me, lnvolvir¡g the ailsorbed. s¡æcies (ZO) "ta

H + ë

a NH Ni Ni Ni "r' ( eo)

H H þ + N N ,t Ni*/ Ni (zt) lhe latter ::oute to ca¡tazole is especialþ irrteresting, sincå it first ir¡volved the fomration of !-cyclohoqrlaniline (Zgb) which is d,el¡yd.nogenated to d.ipherylarnine. J"ck"on,4 has relnrb ed' 7g/" yield' of !-cyclohe4¡rlaniline fnom the reaotion of aniline wj.th oyclohercylamine (26) in the presence of W-/J Raney nickel, althougþ this figulìe vas -1lrr based. or¡ly on the cyctohe)ry]anine, and. the ove::a3.l yieJ-d- was in fzot,2{o. Nevertheless, thls prod.uct shows rer¡arldable stability to Baney nickel arril ind.ioates that this reaction may be a su:itable synthetic pathvnay to

thís and. relatecl compounds. there are three main catal¡rtic rethod,s of pre¡nring secondary Firstþ, a¡nl¡res nay be alþlated. by a¡ni¡res fronr primary "*in""oM yi,eld.s as shown by Ad.kins C"u."ro47 aloohoLs in excellent "nd'

R.OH+R|*NH2ëRù-NIf-Rr+HZA

Th:is reaction bas been adopted' successfi¿\y and is used' corrnonly as a

s¡mthetíc method. for preparing secondary and. terbiary amine".'l+8t49r50

The second r¡ethod. for catal¡rbic aIþlation of amines is with ketones or ald.eþd.es, which prrcbabþ prceeed.s via the jmj¡re intezmediutt.5l

E R H2 R Cs0 + Rt-Mz 6 ø N -Rl ---) CII-NII-Bl R. --€ R R this has also been used. extensively in ¡recent s¡rnthetic *ory.52'53' []re thi¡rl method., a1þJ-ation of amines with a¡nines, wh:idr i's applicable to this series has received. much less attention than the fj.rst two. Ihis reaction was first noticed. by IpatíeJA itt 1908" .He fow¡d. that tgrd.nogenation of ani1i¡re rmlth nickel oxid'e catalysts gave t besid.es cyclohe:rylarnine (26), 1{, yíeLds of d'icyctohery}arn"ine (Zea)

and- f:¡tafeJ6 and. !-cycloherqylaraine (Zgb) o Rosenmr:rrd' Jord.a,F5, ""a founct. that benrylam:ine (ZZ) an¿ ø'-pher¡yletl¡ylaurine cor:ld. both be conver.ted. to the colrespondíng second.ary amines ard. annOnia nrith -7t- pallad.irm oatalysts, but cyolohe:qylamine arrcl anj-Line shor¡¡ed litt1e r.eaP tion ¡:r¡der sjmi]ar oond.itions. Sj¡rr:ilarly, i.n the cata\rtic þd'rrcgenation of pher¡ylcyani-de (ZZ) , it was notioed, that good yield.s of ðibenqyla¡riÍne (25) were obtained..57 Vortsraun5S n"" suggested' a mechanism for tl¡is ¡reaction i:cvolving attask of th¡e Lmine interned'iate (Zi) on the amine (2+) (scrrene 4).

H^ H) C,H-.CH^-M^ c6%.cN -¿> c6H5oCEIeNlf -+, 02 ¿ ¿ 5HU.CH,-N4II.C6E5 (zz) (23) (u)

H^ -¿,> C5HU"CHT-N[I-GÍ Z.A6H5 @)

Sct¡eme l¡."

lyinans an¿ À¿kir¡sÉ n"rr. presenteè an argument to cor¡firm thjs meohanism' consequently, sinae amines- have been shorrrn to d.et¡rd'rogenate to sun" j¡nines on Raney nickel and other metal oatalysts t59 '60 it is not prising that recently K5:ld.Ier and Mathies6l'62 htw proposed' a sj¡rilar

nechanism for the folrration of several alipþatic second'ary a¡nj¡res oger

Raney nickel. lhe fornation of clicyclohexylarnine (Zea), $-cyalohexylariline (Z8U) 54 an¿'d,iphenylanrine (19) from anili¡re has been known since 1908.' Debr:s

ard. Jnnge n63 195i were the first autho::s to publish an extensive ^ stuQy of the tSrcl.rcgenation of ar,riline. lhey showed that short reaction -16- ti.nes and. low temperatures favoured. the forrration of cyclohexylarrine artll d,icyclobe:çylalrine, while more vigorcUs conditions yielded greater quarrti- ties of N-cyclohergrlanjJ.ine. They estabtished. also that if water ig present in the reaction nixtune¡ good yielcLs of cyclohexanone and' cyclo- hexanol wer¡e obtainedo Other workers6¿È have utilized' this reaction in the preparation of dicyclohe:qyla¡ineo Fro¡o these results, Debus ard Jwrgers concluåe tbat the reaction proceeds by Ìryd.r'ogenation of aniline to cyclohe:rylarni¡e follov¡ed, by d.i.roerization to d.icyclohe:qyla:nine ar¡d. cleÌ¡¡d.rogenation to N-cycloharylanilirre (Scheme 5; R ' C6Hil). Ihe isolation of cyclohexanone in reactions in the presence of water inðicate the fo:mation of cyelohe:qylicteni¡rine (27) wnicb is read'iþ Ï¡yd'rolyzecl to the keton" ¿l åS.65 46_ Greenfieltlc has revaeweo most of the work conce¡ned' with the formation of d.icycloherqylamine by Ìryd.nogenation of aniline, showj'ng that aLL steps in the reaction al¡e reverSible. He attempteô to íncrease the y5,eld.s of cyclohe:ryIam:ine in the tSrd"nogerration witkr metal catalysts by add,fug arnmonj.a or anmoniun þd.roxid.e, thus reversir¡g the d'i'nerization reaction, but was unsuccessful because of poisoning of the cataþst.

However, he rnad.e no mention of the formatlon of, {-cyclohe:çylaniline from dicyc lohe:rylanine . Jackson anô sasse ,3' on the ottrer har¡d., have proposed' that N- cyclohe:çylanjJ,i¡e is for¡recl. by attack of aniline on cyclohoqylid'enjmine (Sctrenre without the fo:mation of dicycloherçylamine inte¡med.:iate J¡ R =

ad¡)o lhey also isoLated, oyclohexanone, confirnirrg the id'entity of the

Í.mine inte ¡rred.iate. _7i_

NH IGi eNH 2 2 -.-.--.->. =--- <-- -- HzN-R. (zt) (26) il H lü{ N\R 2 R N./ H (") E = c5H11 Bi tr (u) c6% (ze)

$chesie 5"

f,hey base their argurnent on the fact that aniline, when reffuxed. with w-Ë Raney nicker at 18oo,- gave {-cycloherylarlitine (z8u) as the nai¡ pnod.uct, a¡rd. no d.J.cyclohexylauiüie-.; lrlâs d.etectedo Even when cyclohe:qylasú¡e was added to the reacti,on of aniline with W-Ë Rar¡ey ni,ckeI, no d,icyolohe:rylamine was d.etected., ar¡d. a 9Ú/o conversion of cycloho:rylaui,ne to {-cycloherçylaniline was neported. These a¡thors a1Èo showed that d.iphenylamine and carbazole which al.so fo¡roreil in the reaction we:¡e not converted to {-cycJ'ohexylanilirr".J8 Kbhncke and. Ha¡rÍs"h67 h..r" apparentþ applied. this reaction to the pr.eparation of N-cyctohe:çylaniline , IÞ(J-t"thylcyctohe:ry1)-¡¡-Xql¿id'i¡re (29) ana S-(2-metl¡rlcyclo¡tsVl)-g-toluidine (30), but give very scant d.etai]. on both materíaIs anô method.s" -18-

ctl gII fl 3 5 H

ffi, CH 2 (2e) (¡o) part of this thesis is d.evoted. to the investigation of, the reactions of aniline and. its derivatives over Raney nickel with the object to lea¡n more about meohanisr¡s involved, and to d'evelop a syntbetic pathway to partþ satur:ated- second.ary a¡ri¡es :related' to !-cycloher¡ylanilino' Dr.rring their work, Jackson and. Sasse6S h",r" stuèiecl also the toxici- tíes of ttre phenyl d.erivatives of Gnoup V, VI, and VII elements towards Raney nickeL, a¡d. the tendencies of these compounds to r¡¡rd'ergo \¡rd'rogen- oþsiso In this work they have shovm that the poisoning coefficientt

as measì¡l¡ed. by the retarrclation of lSrd.nogenation of 3l3!g-crpto¡:;ic acid',

i.¡rc¡reases d.ov¡n each Group of the ¡:erioËIic tab1e. Also ít was found' that

Group VI had. the greatest toxic effect, folLowed by Groups vII, and'v in ttrat ord.er. These results have their U¡nitations sj-nce the phenyl cterivatives were lqlrd.rogeno\rzed. d.uring LSrd.rogenation and the variation in stabilj.ties of the pherSrl-hetero¡.tom boncLs nay be nesponsible for the

obse:¡red. trends" . Neve¡tho1ess, ïrith the exception that o)rygen was foturd' to be toxic, this work is compatible wittr the theories of l¡"xted'1J utro stud-iecl the poisoning of ptatinum oatal¡rstso lt j,s surpri-sing to note, i,on'"t"", that in tho sano series of, experi-n ents rS4$9 J*ckson arrd, Sasse for¡nd. -19- tetrapher¡rlsilane to have a poisoning coefficient toward's Raney nickel in the same o¡'der as ohloro.. and. bromobenzene, both of which hyôro- genoþze very read.iþ to benzene and. þd.rogen haliðeo St.""e70 h.s also showr¡ on a spectroseopio scale i-r¡ etha¡¡ol that tetra¡ùrergrl-silarre is cleaved. to benzene, and in bojling toluene over W-7 Raney nickel, tri- pfrer¡ylsíI¿ne] rryâs formeê in smal1 yields as a byep¡¡oducto Àlthougþ there are a nr¡nber of references in th¡e l-iterature to the \rdnogenation of organosiricon compo*a"r71 '72'73 the þdrogeno\rsis of the siJ-ane fi¡nation app€ar not to have been retrnrted. previousþ. Other

Group I\Ib organic cornpounds of tin and. Iead. have been shown to und'ergo l¡rd.nogenolysis ön metal oatalysts .7\'75t76 S.pialter, Buell and' ttarrisTT trave attompted. to hyd.rogenate a1t the Grrcup I\Ib ptrenyl d.erivatives with a rrickel oatalyst ií ord.er to compare ttrej-r abilities to t¡yd'mgenât€r Tetrapher¡rlsilane was the on\r d.erj-vative which cor¡ld. be lSrd.rogenated', the others being reoor¡ered. in yield.s ranging îrcm O-Jfi. Also they

four¡d. that tetraphergrl-germaner -stânnane, and. -plurbane, anfl triphenylsi- Iane all polsoned. the cataþst to varying degrees cluring the Lrydrogenation of tetraphenylsilane to tetracyclohe:qylsilane o They suggested t'hat poS.s-

r oning; occu¡rs by coord.ination of the niokel througþ tlre central atom of these compounds. Initial sterio hindra¡rce in tetrapher¡ylsilane pnevents it from poisoning the catalyst, and. Ìo¡rd.rogenation proceed,s wit,h this

compound.o fripher¡¡Isi.Iane, which is less stericalþ hind.ered.-ôid show

sorne poisoning pro¡nrties towa¡d. the cataþst. It is interesting to note that these workers also found' si'Iane -2(t,^

d,erivatives to poison cata-lysts as, accotd.ilg to ldæcted.r1J it shorrl.d' be i.mpossibre for silioon.to coord'i¡ate with metal catalysts' As ex- plained. earlier, lylaxted" has classified. aII poisons into thnee grouPst the Group fV,b d.erivatives falling into the second.. These aompound.s coord,i¡tate by d.onating electrons from their penultirnate ¡l sheJ.l to empty d. o¡bj.tals of tha catalyst. Silane d.erivatives, however, have the electronic configuration -

2 2 6 st 1s 2s 2p I I I t 5tË

and. have no fÍ]Ied, d shells whick¡ could, possibly coubine 'Jtrith the g oribtals of ni-ckel in chemisorptíon. lfalcted. proposed. that higþer ele- nents 1n Group ftfb should poison cataþsts by d.onation of inner d orbital eleotrons such as in the oase of tetramettgrlplunbane mentioneð earliero As silicon cannot d.o this, a completeþ new explanation for silane ad,so4>tion must be for¡nd. Spialter, Buel1 ard. HarrisTT y^u" tentative}y suggested., without supporting evidence, that poisoning ûray ocqur by donation of electnons to the enpty 5$ orbital of silicono

Some of the work in this thesis ai-ms at acoor:ntJr¡g for this apparent 'anou¡alous behaviour of the Group trVb organies, .A1so, since rargr of these

organosilicon compor¡nds ano extremely stablur78 a new ¡rpthocl of cleaving

silicon-oa¡bon bond.s cou1d. be of conside.lp.ble s¡mthetic value in

orgarro-ruÊ tallic chemi.strYo CII¡{PIER. I

Hydrogenoþsjs of Group lliflo - organo

oompoundso -21-

DISCUS$ION

It has been shown that cleavage of sj.licon-carbon bond.s is coro- ¡nrative\r A:.fficu1t.78 Sllicon-aryI bond.s a¡e tlre most read.iþ cleaved, but this nearþ always i-unolves either electrophilieT9 or nucleophitioSo attack on the arpmatic ring and' usually requil¡es activating gr¡oups in the aromâtio systemo fhe d,i^fficulty of horao\rbio cloavage of organo-silicon bor¡d.s may be i1lr¡st¡ateil fairly accurately by ttre average bor¡d er¡erg of Si.C bond.s (76 Koalr/rro1e) which is on\r sligþt1y less than C-'C bond enerry Gl t

conposition not occu:ring r.¡ntil 5OO-500o.81 t82 Henoe it is sr,rprising that tetra¡ùrergrlsilane nay be cleaved. r:nd.er such miId, cond.j.tior¡s at

tomperertut¡es as lov¡ as 8O-1OOo in a few hours over Raney nickel ¿s sas

d,escribecl in the Introduotiono The first problem in the irrvestigation of this reaction was ttre ohoice of a sui.table solvento Previor¡s Ì¡rd'rogenoþses had' been carrj-ed' out in rethanolr6E Orrt this was w¡suitable beoause of the ¡rcor solubility of silane d.erivatives i¡¡ this solventr and. S.""u70 hacl shorm.that etl¡anol was srritable on\r for :reactions on a speotrosoopic sGa]6. Toluene, altlrougþ a better solvent, is cleaved. over Raney ¡rlckel to give benzetw

and, oyclohexane rT0 *U is therefore unsuitable if yields of these prod.uots fron the reaotion are to be measuredo Ethers are mr¡cl¡ better solvents for these compounds, and. as d.ioxan has a reasonabþ hlgþ boj¿ing point -22-

1tot.5o¡r Ðd d.oes not react appreciab\r over Raney nickel catalysts at atmospheric pressure below 21Oo r3 it was chosen for this series.

Since il-7, W-5, anrl 1Y-1 Raney niclcel had. to be freed. of urater befo¡¡s u.se, these catalysts were washed. with soLvent" To lessen th* expense of waohing wj.th d,ioxan, mettrarlol was r¡sed. initially to :¡emove most of the waterr and this removed. with ùioxan, the final reaction mixture having about 5 voL"4o nethanol in d.ioxan. Ihe rethod. by whicb these reactions weno carried. out r¡vas essentially sirni.Iar to that used previor.,"Iyr68 w:itJ¡ the following mo&if,ioatior¡s. By nefh.ocj.ng the ¡¡eaction raixture on a d.istillation colrrmn, the prod.ucts

(nsnal'l,y benzexte and. cyclohexane) oor¡ld. be removed. convenientþ frm the reaction si.te by ¿lisfi11ation, årnd. the path of the reaotion followed. by the boiling point of the d.istillate" the gmall qr:antiti.es of nethanol præsent in lhe solveat were therefore r¡.sefìrl in ftat it fororea an azeo- tnope with benzene ard. cyclohexane, and. thus removed. most of the products before the distil,late boiling pojnt reacl¡ed. 650o This was usualþ aotrieved. in about two hoursr after wtrich the temperatu:¡e at the top of tÀe coLumn rose at a steaftr rate to 1010, and. the ¡¡eaotion was stoppeiL after about for¡r hours.

Tield.g of, benzene and. cyclohexane tlrere d'etemi-ned' by gas chroma- tograplgr, or if the solutions we:¡e too wet, the concentration of benzers rras d,eterroined. by its r¡Itraviolet absorption, and. the ratio cyclohexane- benaene detenr¡ined. by gas chromatograpþr from wÌ¡-1ct¡ were calcr¡-lated. tho yields. The accuraçÍ of this proceêu:re sras d.emonstrated. by blank runs _23* in wirich benzene, instead. of the silane, was ad.d.ed. to the catalyst, al;rd 9V" of the starting naterial v¡as accounted. for. Preli.minary experinents had. shown tfrat ò.06 moles of tetra¡ùrer¡yl- sila¡e with ïf-7 Raney nickel frcm 12J g of l:1 nickel-alr¡nínir:n alloy

Save \5% yie1d. of benzere ard. cyclohexane, rul¡iIe 0.018 moLes of silane to the samÉ' quantity of cataþst yie]d.ed, about 6ø-lV" þd.rooarbon mixtuæo Ðxcept for a few ex¡nrj-rnents, -this latter ratio of silar¡e oatalyst was r¡sed. througþout ttris series. Most e:çeri¡nents were carried' out in reflr:xing d.ioxan (at appr.oximate\r lOOo). Neverthelessr several silicon-phergrl d.erÍvatives were fou¡rd. to cleave, thougþ much mo¡e slowþ, at room temperatureo TetrapherSrlsilane or the vario'r¡s phenylchlorosilanes were pre¡nreil from silicon tetrachloriile and. the required. qrrantity of pher5rl lithiun accord.ing to the rBthod. of GjJ¡nan and. CIarkoSJ nror example, ad.d"ition of three moLes of pher¡¡Ilithium to one mole of silicon tetrachlorjde gave triphergrlchlorcsilane, whioh on treatment with nettsrlnagnesiun j.od.ido gave triphenylmethylsiJ,ane, Hyd.rolysis of tripher¡ylchlorosilarp with a weak base gave triphenylsilanol whicle, with fo¡rr¡ic acid', gave hexaplaeqyldislloxaneo The other $rer¡rlrnetÌgrlsilanes, silanols, and. siloxanes were similarly s¡mthesized.. f,etra{¡-to1y1) silane vras prepared. by treatnrent of ¡-toþIJ,ithir¡n with silicon tetrack¡lorideo. This u¡as oxidized. with chnomir:n-trioxide to tetræ(¡-oartrorqyphenyl) silano by a method. sjntilar to that of GiJman,

Brar¡r¡en and, Ingþarn.q -2þp

TABT,E T. the aation of llÍ-7 ard. related. Raney nickel catalysts on organoÉ

sjJ.anes z /o Lj.;eLðs'.

Mai-n Products Starbing Other Products Gompounds Ar.omatic Aliphatid tota]" MateriaL

S.i 19 47 66 (ceur1)¡ri 1"¡

si (Ë) 33 4B 81

si (c) 5+ ?+ 7B

si (¿) 12 60 72

si (e) 3 (r (¿* 96

51 12 6l 17

26 1+ 60 20 (ceHr1)¡si, I ; Siloxanes (a) PlSiMet % l+J 67 32 (cgn,¡1)osi, I ; urersi(crnrr) (s)

Methane (a) t

SiJ.oxanes (a) o

þ-*recrun)¡si 38 25 6l 3o þ+oou c6lrt si (r) aào 25 9o 25 5O ?J 22 l+5 22

,u)z 4o 6 \ß

PÌSsicEt ?)+ 15 39 Ethanol¡ 5c

Phjs,i6iPhl 2 12'. llr )+5

(a) 10 32 l+2 -25-

EABLE r (conta")

Main Pnoduots Starting Other P:¡oducts Compoud.s A,¡omatic Aliph,atic fotal Material

(ue¿isi) 16 lrB zo(a) 32

(rnrsio), 1 6 7

(ern )4sr none none 92 (ceur 1)siuu, nono nor¡Él (c6H1t) jsi none none t 87 Benzere 6l 35 98 -

Methar¡ol Uethan,e.(a)

(") DetecteiL in inf¡'ared. speotrao (u) Ill-l Raney ¡rickel oatalyst.

(") ïltr*1 Raney nickel catalyst"

(a) Rieaoti.on carriecl out with exch¡sion of methar¡ol.

(") &aney cobalt oata-lyst. (r) Reaotion cartied. out i¡r aqueous NaIICO, solution' (e) Detectecl by gas chronatogra¡ù5r. -26'

B oth tet rracyolohe:qylsilane and. cyoLohexylt rine tlsrtsilane were pnepared. by tryd.nogenation of tetra¡*rergl- and. pherSrltrimethyl-silaræ respective\ro [he nethod. of l{anazashi and. lakalos"85 *"" r¡odjfied' for the r¡se of vü-7 Raney nickel, giving sligbtly better yields of þcirogenated. prodrrcts. Attempts to prepare tkre previousþ r¡nk¡onn¡ tetracyclohexJrl- gennane from tet¡"a¡henylgemane by the sane prooed.u:re failed. The results of,a series of organosilanes treated' with Ïf-7 Raney nickel ia d.ioxa¡¡ j-s shovrn i-n Îable Io Blank Epaces ir¡d'icato that the particular yield. was not lnoasüredo

In this series of experirnents, ctifficulties '¿vere experienced' i¡r the neprod.ucibitity of the yield,s of benzene and. cyclotrexano, and' variations of up to 1Úfi were co¡nmono In most oasesr arl ave¡¡age of at Ieast two experirnents were necord.ed' to ¡ui¡ui¡lize this êf,roro It is not known what eaused these variations. In the cleavage of tetrapherlylsilane to benzene arrd, cyclohexane, it was consid.ered. that sterio effects rnay exert some contnoL on tbe the :¡eli.ef of sterio cro¡¡d'i¡rg of the four ¡ùer¡yI reactionrT7 "lo"u groups by erçulsion of a benzene moleoule wor¡-ld. suppliil a d'rivi-ng force for the initiation of the neaction. Consequentþ, the compound's tri- pþer¡ylmethylsiJ,ane , cLiphenyld.i-metlrylsil¿ne, md pher5rltrjmetþlsilane t aII havi¡rg less steric crowd.ing of the sr¡bstiuent groupsr weæ tested. Inspeotion of Tab1e I shows that lr¡:ltJ¡Í.n experimental error, these oompouncls aIL gave yield.s of benzene and. cyclohexaræ comparable to that from tetrapher¡ylsilane, from which may be conolud.ecl' that relief of sterio crolvd.ing has little or no control over the reaction. -27_

Si.milarly, eJ.ectronic effects on this cleavage rrere examinecL by treating tetra-þ-to]yl) silar¡e and. tetra-(-p-carboxyptieqrl) sll,ane with

W-7 Raney nicke]-o Tetra-(lg-toþ1) silaræ gave toluene and. metlSrlcyclo- hexane i¡ si¡nilar yield,s to tetrapher¡ylsilaræo The yield.s of benzoic and. cyclohexanoic acid.s f¡¡om tetra-þ-carbo4¡4pheny1) silane were lolver by about 1qo, :or:i- it is not clear whether this is sj-grrificant, as the reaction had. to be camied. out in agueous sodir.¡m bicazbonate solution rather than j.n dioxan-metlranolo It is r¡nfodu¡rate that other eleetnon- withôrav¡ing substituents which cou1d. be r:sed. in place of the carborylic ac5.d. group r¡vould. interact ind.epend.ently with the cataþst" Horvever, it may be conclr¡d.ed. that electron-withilrawing or d.onating substituents on the pher¡yl rings have'comparatively'little effect on the rneaction yield's. liignificantþ lower yield.s (approximateLy \Ú/) of benzene and. cyclohexane we¡e obtained. hovrever, from tripherSrlsilanol, d.ipher¡rl- siJ-aneùiol and. tripher¡rlethor(ysilane. the siloxanes were for¡nd to be the most stable compor:nd.s with Raney nickel. Hexapher¡yld.isiloxane gave

1t{o yíeLd, of benzene and cyclohexane, while hexa¡*rer¡rlcyclotrisiJ.oxane gave onþ f/o tsnder stand.ard. conditlons. Hence, dI comporrrd.s with o{ygen functions were found, to give 1-ess yield.s of benzone and. cyclo- hexar¡e tha¡r other silanes. Several reactions vrere carried. out with catalysts v¡hich had. been r¡vashed, onþ in d.ioxar¡ and. the¡refore contai¡¡ed. no methar¡olo In errery case, the yields vrere corfs¡id.erably inc:¡eased., suggesting that methar¡ol midrt exerb a djstjnct poisoning effect on the cata\rst. Tetraphergrl- silane yiel¿e¿ J{obertzeræ and cyclohexane, while hexapher¡rldi-qii-Loxane -28. and. g¡4qr¿ipher¡yltetrarnethyld.isiloxane gave yields bet'reen \trÁ aûÅ' 5g/". tetracycloherrryIsilane rrras treated. with W-7 Raney nlckel to d'ete¡' ni¡re nÈrether aIþI groups could. be removed. by this proced.une. This oompound was found. to be stable, Md ïras recovened. al¡rost quantitatively from the catalyst. As this r:nreactivity may have been car:sed by the cc¡rsiderable steric hind.rance of the four cycloherq¡I groups, cyclohe:qyI- trimettrylsjJ.ane vras also tested. and. for¡nd. to be sirnilarly stable the same cond.ition"so It can then be conclud,ed. ttrat at least one pher¡rI substituent is necessary befone fission of an¡r silÍcon-carbon boncls wiIL gOCüfo

It was shown that aIþI groups corfld. be cleaveil. from sj.licon if pheryl groups are also present, si¡rbe ætjxane was d.etected. from pher5rl- trimetÌ¡ylsilaneo Methanol alone reacts over Raney nickel to give methane but i-n much srna}ler yie],i.s ur¡d.er these conflÍtio¡so Ünfortr:nateþ, these gaseous prod.ucts weæ ruixed rm:-th about four to five U.t:res of þd'rogen from ttre catalyst, a.nd. yielcts could not be measureð ùirectly" perhaps the most uil¡sual. nesuLt vras the fon¡ration of tetracyclo- he:ryIsi1ane j.n the reactions of pherlyttrimettlylsilarn and. d.íphenyldinethyl- silåneo ¡alysis by gas chromatograpt¡y of the liquj-fl residues from these neactions i¡rd.icated. a nr¡'nber of other components in snrall yield's inclu- d.ing cyclohe:qyltrimethyS,silane. Althougþ the other compor.nds wene not checked. by stand.ard.s, tJaeir retention times ird.icate that they nay i$clud'e ðicycloheayldi-urethyLsilane and. tricyolohe:rylmet}5rlsiJ-ane" The infrared. speotra of these liquid. resj-dues also showed' broad. strong bands at ad at cro-l 1rlOp-l rOO0 cm-î char.acteristic of siloxanes, 5 t6OO-3rl+0O -2q- charaoteristic of si1"rro1so86 lhese saturated. siLanes and' þd'no:q¡- siloxa¡¡es were the on\r by-prod.ucts d.etected. in ar¡¡ of these }o¡fdnogen- oþses. lriphenylethorysilane gave ethanol in about J6l yíe1:ô', but this need. not be fo:xred. exch.:sively by cataþsis, as attack by þdroxid'e on alkolysila¡res i.s hrown to c¿use Lryd.:ro1ysis.B7'88 Because of the basj-city of lV-7 Raney nickelr5 a neutral '!f-5 B'aney nickel eataþst yas employed. to test vtrether this alkaJ-inity contributed. to tl¡e cleavage of these compourrd.s. iù.lthou& Vl-5 catalysts contain less

þyd.rogen, j.t was found. that the yield.s of benzene and. cyclohexerrie were increased.o Sj-milarly with a Tf-l catalyst, which has a smal.ler lSrd.rogen content than tü{, tbe yields of t¡rd.rocarbons fro¡n tetra¡irerSrtsilane Ïlere better than for W-/ Raney nickelo These results ind.icate that a L5rd.rcgen richr catalyst is rrot necessary for good. yi.elds j:n this reaction and't in fact, excess kgrd.rcgen may hind.er the oleavageo

Shese results prompted. experinents with degassed. Raney nickelr anê ao expected., the yi.e}d.s ìiyetiq even higþer than for Tí-1 aJId' Í['-l catalysts. [he results of t]¡e action of d.egassed Raney niolcel on several organo- silanes is shown in lable II. Once again, the labilities of tet¡a¡henylsilane, tetra-(:ltofyf)- silane and. phergflmethylsilanes rffene apProcimatgly the sarne, and also gave best yield.s of benzeræ and. cyclohexane. A,s with W-7 Raney nickel, tri- pher¡y1silanol and. gg-d.ipher¡yltetrannethyld.isiJ,oxans gave lower yieJd.st but ia this case were wer 6Úfo Erom this it may be cor¡cluded' that the -3C-

ÎTBLÏI ÏT lhe action of d.egassed. Raney niakel on some organosíIanes â {o Y,ieLds.

Conpour:ô Aromatio Aliphatic TotaJ.

Ph.Si. 13 g1 5 biphenyl, J ; 4 78 (cgnr 1)nsi, 1 o

3z 5 37

5O 16 66

6S 25 9O biphenyl, 3 i Siiloxanes (a). nrrrsilte, (b) 50 1't 61

Pls,ilÍe, A+ 27 91 5 biphergrl, J ; (eirue¡si)ro ; Methane, 8/.

PrSi-ue, (b) 35 22 57

(!-Mec6H4)rj}¿ 77 13 90 3

55 11 66 biphergrl, I i "nf* siloxanes (a).

(rnuie¡i)ro 45 20 65 20 biphergrl, '! ; siloxanes (a).

Benzene 75 22 97

(") Detected. i¡¡ ir¡frared. spectrao (r) Methanol @. ZO mf) ad.d.ed. to reaction mixtureo -31- orùy d.i-fference between degassed. and. l{-/ catalysts is in the efficienoy of tgrd.rogenoþsis, In earlier experiments w:ith d'egassed catalysts, methanol (approxi.rnately 5 vol/') was added. to the d.ioxan before commoncíng the reaction so as to sj-muLate cond.itions used with iÍ-7 cataþsts and. to help ¿ìistriI the pnoductso In these cases, a very s¡arked. d.ecrease i¡¡ yield,s lras obsenred.o TetrapherSrlsilarre shou¡ed.a d.zop in yield's of benzene arxl cyclohexane îrcn )1/" to 37Át while d-iphenyld.irnetþlsilane and. phergrltri-methylsilane showed. a d.ecnease i:r yieJ.d.s of about 5e/"" Thi-s red.uction in yield.s must presurrabþ be cat¡sed. by poisoning of the cataþst with methanolo This is unr.¡sual si¡¡ce aloohols have been used exte¡rsively as solvents for margr oatalytic reactions o16t17 '18'68 Hou¡-' arrd. lveirb have shov¡n that pri-urary aliphatic alcohols ever, Meyer]¡r "r¿'l reaot with nickel eatalysts to fo¡r¡ the next lower honologous alcoholo They postulate this to occur by d.ehyd.rogenation to the ald.el5rd'e fo1lowed. by eli-nination of carbon monoxide w}rich rnay be Ì¡rd.rogenated. to methane.

They have shovm that rBthanol gives both metbane and. carbon ðioxj.d.e over a nicl

f, et raphe 4yI s il-ane, t riphe r¡ylmethyls ilane, an¿ t e t ¡¡a- þ-tofyf ) - silane and. d.ipaergrJ.silaned.i.ol were found. to react at rroom tem¡rratu-re wer W-7 or d.egassed. catalysts.to give correspond.ing lSrd.rocarbons as shov¡n in lable LtI" In every caser the yield's of benzene and cyclo- hexane afterl+8 hours were less than for neactions at 1OOo, arrd. starting materials were recove:red in gneater quantitieso However, even thougþ the

¡¡eaction is much slower at room temperature, this sti'ìI ind.icates that ú3-

T¡BIE TIÏ the action of Raney nickel on some organosilanes at rcom teuperature : f vi.elas.

Main Products Sta*ing

Conpound. Cata-1yst Aromatic &liphatic Iota]. Materia]-

Ph,S'i W-7 2 t7 60 + t5 Ph,si w-ru 21 1 23 68 + enfile Tr-7 55 6 61 31

þa,aecruo)usi IV*7 (") (") i10 12 8J{- Phisi(oir)2 w-7 '!6 2 r8 80

(") these yield.s wene not d.etermined' accuratelyo the conðitÍons for cleavage of siU-con-carbon bond.s with Raney nickel may be very m:ildo to test tlre ef,fect of the etectron:lc struotur"e of tho central atom in this reaction, a comparison was nrad.e of cyolohe4yl and. phenyl d.erivatives of all the Group I\[b elements. lhese results ane listed. in lab1e IV" Tetraphe4yl¡rethane was founè to be unaff,ected. by degassed.

Raney nickelo Triphenylca¡binol qhowed. no carbon-ca¡lcon bond. cleavage but onl¡r und.en¡¡ent Ì¡rd.rogenolysis through the o4yçn atom to give tri- pheny1meth"rr".90 Hence, carbon analogues were four¡d, to be r¡¡reactive to Raney nickel tx¡d.er these conèiti-ons. 4F

TABI,E TV

T.he action of Raney niokel on Grrcup Ilrb-organo cc'npound's z % Yield'so

L/Iain Prodr¿ct Compourrd. Catalyst Aromatio ÀJ.iphatic lota]. elcou(a) yr-7 none none

Ph, c Ïi-7ür none none ¿+ 66 Ph, si vJ-7 19 l+7 + Ph. S,i ]jv-ït 78 '/3 91 + (cuu..r)¡ri lY-7 rrone none eh¡c7effi Tf-Ë 76 21 9V

Ph+cz" l¡V-ä 81 16 97

Ph. Sn l[-7 )+9 41 90 l} çcrn.,1)aln (b) I{-7J none none - (crur,,)unu W-Ë g1 91

(") Triphergllmethane, 9U/o " (¡) Sitarbj¡rg material recovered., 9flo.

we T et raphergrl gennarre, t riphergrlge rmanol, and tet raphergrltin re and' cyclo- cleaved. very readily giving yieJ-ds of over 9g/" "f benzene hexa¡e, even with W-7 catalysts. Tetracyclohe>rylstarurane was found' to be stable to degassed. catalysts and. was l¡ecove¡ed. w¡changed. letra- cyclohe4ylplunbane, however, gave a )1/" yield. of cyclohexane rvith d.egasseô Raney nickel, but this riay be anomalous to this seriest as K"",*u91 has reported. that this lead. compor:nê vras unstable, and. d'econ¡' '35- pobed. nead.iþ on standingn Îhe lead.-carbon bond. would. therefore be expected. to be r:¡stable toward.s hornolytic cleavage, for example, by kgrdrugen atomso Hence, with the exclusion of Iead., these results ind'ioate that aIL the Group IVb compow¡ds except those of carbon show the sane tSrdro- genoþtic propertJ.es with Raney nickelo If phenyl sulcstituents are pnesent, then the organometallic bonds may be cleaved quite :read.iþt with the ease of ¡eaction incneasíng d-ovrn the Group" rn orrler to propose a mechanism for these :reactior¡s, it is necessaty to first ur¡derstand- how the reactants are ad.sorbed. onto the catalyst" In the case of tetrapherlylsilane, two possibilities must be ccnsid.ereô; ohemiso4rtion througþ the tf-electron system of the pherSrl r]ngs, or ctremisorption througþ the sil"ioon atomo Evid.ence for the former of these two suggestions is laoking, vuhil-e the latter proposal would. j¡rvolve a complete\r new mecha¡ristio appnoacho If chenisorption did. occur througþ the pherSrl rings causing cleavage of the silicon-ca¡bon bond.s, then a great d.eal of d.esorption woìúd. be by hyd.rogen attack giving large yield.s of cyclohexane com¡nred with benzene, which was not obse:r¡edo Comparison of Tab1es tr, II and. III show that an increase in the hyd.rtgen content of the catalyst, or an ine:¡ease i¡r reaction temperatr¡re both favour the fo¡rnation of cyalo- hexanoo On the other hand, reactions j:r rvhich the ea.talyst was parbialþ poisoned. with methanol showsfl a greater proporbion of benzene in the productso These t¡ends inòicate that cyclohexane was forned. by the Ìgrd.rrcgenation of benzene ¡ and. berøene must therefoze be the primary -J6* prod.uct from cleavage. äitrong evid.ence against cleavage by ad.sorption througþ phenyl rings come from the obse¡vation that both tetraphergrlmetha¡re and. triphergrl- carbinol showed. no þd.r-ogenoþsis of pher¡rI groups und.er equival,ent oon- d.i-tions. Thus chemj.sorption of the arpr¡atic system must lead. onJ¡r to

hyd.rcgenation ard not \rdrogenolysiso . Support for a mecha¡rism involving chemisorption by d'irect nicl¿

the atorolc properbies of silicon conpound.s have been d'escrjbed in reasonable ôetaiJ. elsev/nere ,92e95 but they may be brieflLy sunrnarized by cons5-d.ering the effect of the five outer d. orbitals on the valence shBllofsilarres.Normaltysiliconcompounclsareconsideredtoexist 4 i¡r an l!- hybriùized. state, ud hence like carbon are ¡e!¡¿r¡aIe.,t.9b However, if the sr¡bstituent groups are eleotronegative enoUgþ to induce a positive charge on the silicon atorn, the outer d orÈita1s will con- tr¿cto In mar¡y cases, this is s',fficient to al-ter the enerry and' spatial nrj:c and properties of the .¡l orbitals so as to allov¡ them to with € -P

oribtals of the valence shell, an¿ for:n hybrid.s of the three =he11s"95 Because onþ trvo of the five ! o¡bitals of silicon are oî í' s¡rnuietry relative to the tetrahed.raL d-bonds, on\f these tvro may parti-

cipate in extra bond.ing. They may associate by forming s!5g o" -EI5g2 lrybrid.s 1n one of trvo salso Firstly by accepting electron paj-rs from other moleoules or atoms, or second.ly by accepting electrons fron 1f- orbitals of srrbstituent up""i"""9'] This latter eranple of (p + d) Tf- bonding is known as back coord.j.nation, and. has been shor,vn to occr-u i¡r mary¡ silicoll compound,s where a sr¡bstituent has electron pairs (such as olrygen, the halogens or nitrogen) or 1t'-oricital eleotrons (as ia pher¡yI

rÍngs) vftich may coorriinate with the siJ'icon atorno The fi¡st is il"Ius- tnted. by numerous examples of, penta- and. hexavalent silicon com;oound,s which have been investigated recentty.g5'96 Consequently it is quite reasonable to suggest that the silicon

atom vrill accept a pair of electrons into the .¡] o¡bitals from tle catalyst in chemisorption of tetra$renylsilane to Raney nickel, foruring a penta- -3u valent inte:r¡red.iary complexe Ihis complex will have consid.erable d character in the valence shell. Ihis postu-late is i¡r contrast to Mocted.ls theory which preposes that chenisorption of all poisons to transition metal catalysts is by donation of electrons from the sr¡bstrate to the ; cataly"tolJ Even thougþ the silicon atom may ailsorb quite strongly to tlre catalyst, this stil-l. d.oes not preclr¡r1e the possibility of chemisorption of the phenyl rings during the sane reactiono In faot, it is sff¡i"saged that tmo reactions must occur simultaneouglJr or¡e involving chemi- sorytion of the phenyl ring lead.i¡g to Ì¡rdrogenation, and' the other througþ the silicon atom leaòing to hyd,rogenolysis (Scneme 6).

-SiPt. Ni siPhr+ H2' si(o6H1r)4 ,l+ I útrli

Scheme 6o

trhe kSrd.rogenaticn has been shov¿n to proceed. smoothly r:nd.er a large pressure of hyd.rog unr71o85 .,,u,oi"h would. be expected. on the basis j¡r of Le0hatelierr s principL. r9T since there is a large d'ecrease the nurnber of moles of reacta¡rtso The cleavage neaction, on the other han¿, would. be expected. to d.oraj¡rate at atmos¡lreric pressure, since there is litt1e d.riving force for the hyd.rogenation.

T'ho coo¡d.i.nate1y bound. ad.sorbecl species thus formed. v¡or¡Id. be expected. to be very wrstable and. reaot by two method.so First1y, it may d.esorb from the catalyst and. regenerate the silane, or second.lyr it roay -39*

ejeot a phe¡¡rl anion leaving a tri.substituted. silyl species covalently bounil to the catalysto In the case of tetrapkreqylsil¿ne, Ioss of a p¡rer¡y1 anion leaves a triphenylsilyl group linked. with niokel (Soheme 7).

Subsoquent cleavage of the remaining pkrer¡yl grouPs wor¡-Ld. proceed' by attack of L¡rdrogen as proposed in d.esr:lphurization mecl¡anisms ..,16'17'18'89 Prcducts from this lSrd.rogenolysis inch.rle loezene anrl bi¡ùre4yI, vrhich

were also fo¡med. during d.esulphurization of phenyl d.erivatives of sulphur¡

"wi € +Ph - Ni + Ni +

fl. / PhfjoH PhJi Ph.Ph I ê'; 0 LJ,¡ ,n5 "nJsi

Scheme 7"

cleavage of the nickel-sj.licon bond by [yclrogen, after ejeo* tion of the first phergfl group,- would. give tripher¡rlsilaneo lhis was not deteoted. l¡r any by-products ind.ioating that the strengt'h of this bond. is greater than tliat of the si-1icorr.-pher¡r1 bond.s of the ad.sozbed' species.

Hovrever, attack by hydroxyl ions wor¡-ld. give tripherSrlsilanol, wlulch was isotated. by Sasse6g ,r"itg toluene as a solvento Tbe presence of mixtr¡res of silanols an¿ siloxanes is i¡rd.icated. by the infrared. spectia of the

residues of reactions camied. out in dioxan' This corrlð arise by -}Q- subsequent b¡rdrogenoþsis of the O"4f bond' with Raney nickel to give various sj¡oxanes, accordi+g to the stage at which the siJ.ico¡r-nickel bondr,¡as-c]"eaved'oThesma]"]-eryield'Softheseproductsinreactions ca¡-¡.ied. out in èloxan nåy be explained. by the solvation of t¡rd'ro:grl ions with the rnore polar solvent, hence netard.ing attack by these iongo Sroro this postulated. mechanisrg, it may be exptr ained' ÏrhJ¡ a pher¡rl strbstituent is necessa¡y for ar¡¡r cleavage to occuro Ðirstly, the pherSrl sr:lcstituent lrril^} aot as an electron-attracting group (or rrÊlestroa we]}rr) on approach of the nickel to silicon, thus cr€ating a slight positive charge on the silicon atomo This car:'ses contraotion and. a nickel- of the ¡J shells of silicon as desoribed. earlier er:ables silicon bond. to fo¡m mone readåþo , Second.ly, o¡¡ce the phen¡y1 substituted- sjJ.ane is ad,sorbed., it couLd. quite conceivabþ ejeot a phe4yl anion which has its negative charge stabilised somewhat by conjugationo This eonjuga- tion lov¿ers tho activation enerry for this crucial step in the reaction"

A compound. such as tetracyclohe4ylsilane, on the other hand, v¡orrld have great difficulty in chenrj.sorption sj¡rce there is no i¡rd'uced' charge on the siticon atom, ar¡d. even if this barrier was ovenoomé, the ejection of, a cyclohà:ryl anion is extre¡nely unU.ke1y. Aliphatíc carban:ions car¡not be stabiLized. by d.elocalization of the negative ctrarge, and hence a very higþ energy of aativation would. be required. befo:¡e ejection of these species is possibLe. Consequently ali¡fratj.c substituted. silanes, i.f ohemiso¡bed. at a-II, woul,i very quick\y d'eso¡b again, givi-ng starting materialso ' -f,1*

Pher¡yltri-nrethylsilane gives the best ilh:^stration of the coraplete reaotion mechanismo Chemisorption to the nickel and. subse- quent expr:lsion of a phenyl anion r¡¿oìr1,1 leave trirnethylsiþI-nickel complex, which uhen attaclced. by Ì¡rd.rogen on the silicon-rnethyl bond-s

yield. 'r,he obse¡ved rethaneo Ai-te¡nativef,fp rnethal:e cou.l-d. be liberated' by atteck of phenyl grou^os on the i:atermed.iary complex, giving a pher5rl substituted ad.sorbed species. By a series of these disproportionation

reactions si-¡q'ilar to that d.escribed. by Nelson, Angelottirarrd''tul*yerrberggS

it woutd. be possible to buiJ-d up a series of compowrds such as tetralùenyl-

s j-l-a¡e, triphorSrlmethylsilane , and. d.iphenyld.irnethyl"silane o Tetrapher¡r1- silane, a.fter d"esorption, coul-d be kryd.r'ogenated on the large excess of

caterJ-yst and. l¡rdrogen to give tetracyclohexylsilane which was isolated' in sna}I yields from both phenyltrimethylsilane and. diphenyld.imethyl- sila¡reo The other intermed.iary by*prrcducts, althougþ not isolateô,

have been shorun by gas chrornatograpkry to possibþ exist" trn a1-l previousþ postulated. meehanisms guoted. in the litera- ture, there are no cases in which compor:nd.s are olai¡ned to be chemi-

so:clced by accepting a pair of eiectrons frorn a metal oatalyst" ¡tuxte¿1, clai-ns poisoning and. chemisorption occur by donàtion of eLectron pairs , from substr¿te to the eata}yst, a vj.ew whj-ch has been wiöely accepted."

There are a fsw exampl-es vlhere nickel is pres''aned. to d.on¿rte single elect5ons to the adsorbatez[ u, mentioned. in the Introductiono liowever, aparb from the work by S;pialter:e Buell and. Harri"r77 irrt"raction of

orga¡osi]a4es with metal catalysts kras never been reported" -¿+2-

Sùpialter, BueII, an¿ Harri.s77 u"i"fty mention the poisonlng of nickel cataþsts with trj.¡krer¡ylsilane, but clai¡¡ that tetrapher¡r3-- silane has little or no poisoning effeet. They have tontatively sugges- ted, that a neiv rechar¡ism must operate, perhaps involvi¡g coonlination through the rrenpt¡/t d. orùitaIs of silicon, but they e]raborate no fi¡rther. However, it is noticed. that in aII cases where electron d'ona-

tion fr.om the catal. yst i.s proposed, that reactions are much more efficient vri-tb d.ogassed cataþstso This is probab\r beoause there are more Têao- tion sites available for chemisorption on renrova-l of L¡rd'rogen, arrd' the lSrdrogep content of the catalyst is not cnitical for the neacti-on to

proc9eco-24

The dependence of hyd.roge¡r in this reaction is illustrated' by the very lovr y1elds obtained. fro¡n Raney cobalt catal_yzed reaoi;ionso Raiey cobalt is larovrn to retain very little hyd'rogen99t100 It is not tikely that the activation enerry for this reaotion is too higþ for Raney cobalt to operate efficientlÍr but the basis for this catalystrs r.¡nreactivity is more likely to be the lack of tSrd.rogen available for hyd.rogenolysis.

14f-p Raney nickel, althougþ having lost a oonsid.eralrle portion of its t¡rclrogen, still has enougþ to give good. yield's of lSrd'rocarbons

by kryd.rogen attack. Rougþ ca-lculatiorrs from the '¿ork of Kokes and' Emmettll as j.Uustrated, by Sasse and Ïlhittt"Z4 io¿icate that V[-Ë

Raney nickel d.egassed at 1O0o v¡owldl. retaj¡r approxirnately )a2 cc of þdrogery'g of catal,ysto trn tk¡ege reactions where about 62.5 I of catalyst vês ¡r""U, this could. supply O.12 noJ.es of Ì¡id.rogeno Assuuring *43- that four moles of hyd.rogen tvouJ.d be ultinrately used. in the hyd'rogeno\r- sis of one mole of tetrapheqylsilaneu this corresponds to 0.O12 mol-es of t¡rd.rogen requir"ed. for cornplete cleavage on the scale at v¡hich these ex.oerÍments vlere carried out" Hence, these reac'cions oVe:' d'egassed' cat4lysts lvere carried. out vrith approximately iÚ/o excess of hyd'rogen, enabling goocl yield.s of benzene and. cyclohexane to form" It is interesting to note that in the zeaction over 1[*7 Baney nickel rvith 0.06 moles of tetralCnenylsjJ.ane (which rrequired. 0o24 moles onIX yíeLð, of hydrocarbons of Ì¡yd.rogen for complete cleavage), \i"y' "vas obtai¡red.o This corresponds to 0"11 moles of hyd.rogen used j-n hyd'rogen-

olysi-so assuming that the Yì¡-7 Raney nickel loses as much hyd.rogen at the neaction temperature of 1OOo as'Vf-p when d'egassed at lOOo, this constitutes al,l the hgrd.rogen available for l¡rd.rogenolysiso Ho-'*leven, althougþ these fj-gur.es agree ¡s¿5e¡ab1y with the observed resul-ts r this argrznent is compli.cated. by other factors such as poisorring of the cat'a- lyst by solvents and. hyd.rrcgenation of benzene to cyclohexane, both of which consì¡ne þd.r"ogeno Consequentþ, an excess of hyd'rogen is d'esirable in the reaction, and. in faot gives vely good. yield-s of the required'

prcd.uctso

It was noticed. that silanes vrith o{ygen fr¡nctions such as silanols, silaned.iols, and. sj-l"o:canes, gave markedly lolver yield.s of

benzene and. oyclohexane than those silanes vu4thout olygen substituents"

This j.s unusua-l, as it vroul-d be expected. from the postulated' mechanism

that the eleotronegative o)cygen would. be a far better leaving group than a phenyl arulon, anô henoe an increase j-n yield's would- be expected. -]y'+- from these cotnpound.s ' One possible explanati-on is suggested by the obse:¡¡ation that methanol consid.er¿bly poisoned. the catalyst during these experjments'3'l''!01

Consequently, it ¡nay be envisaged. tl:at the ovJrgen atoms bour¡d' to si'licon nay sirn:ilarly interact v¡ith tine eataJyst, an'i eompetition for reaction sites between o{fgen anfl silicon atons would' reùuce the efficiency of the reaction. However, as d.iscussed. earlier, the o{fgen-silicon bond' is consid.eï.ab}.y d.jfferent fron caxbon-cxygen bond's, due to back coordina- tion of lone-pairs of electnons from o{ygen to silicon. this would make chenisorption of silanols and siloxanes througþ o4ygen much less likely,

and. the¡.efore this method. of reaction reta¡ú.ation may be of sinaLl irnportanceo Tnis is exeinplified. by, the fajJ.ure of R'¡sfrton75 ar-1 previor':.s v¿orkersl02 ro arylo4ysil-anes vrith Raney nicker" "L"^ve Q¡cg agaín, the ansl?er to th:ls question may ILe in the nature of the organo-silicon bond. Si-licon-oXfgen-silicon bonds have been shovr¡r to have a bond. angle of approxiaaately 1¿+O-150o which is corusistent with a r¡y'brid.ization of the o>¡ygen aton bet,¿reen g! and s!'.105t1o\ rh:is vrould place the o:çygen lons-pair eleotrons in 3 ozùítal.s, wìlich may then overlap rvith the silicon ! orbitals in back coond.inatioo.tro5 the silicon oxygen bor¡d. wouÌd. then be expeoted. to be much shorter, and. the force sonstants much higþer, than v¿ould, be expec'ced' for simple ci--bond's, ad this has been repo"t"a'i05 the observed. bond. angles (in most cases of ,tlp-l5oo) sqggest that both 1one-pairs of oxygen occupy p orbitals, and hence, both may coorrlinate r,¡åth the two available d. o:biials of silicon (see earlier discussion). This vìreuld. then considerably reduce -+5- the availability of the d. orbitals of siU-con for chemisozption to Raney nickelr and. so :educe the yield.s of benzene and. cyclohexans in these :¡eactions. ' The er¡idence for back coord.ination in pheryl d.erivatives is much ¡no¡e obscure" It has been suggested. from acid. d.issociation oon- stants and. base strengths of silyI-substituted. arou¡atic acids and. basest that the f-orbitals of the aromatío system njight cor¡jugate with the d. orbitals of sjJ-i.orroto6"o7 Ho'rever, the r¡ltraviolet spectra of trimethylsilyþenzene arrl 3-butylbe r\zer7e were found. to be very sim:if""108 suggesting on the other hard that no conjugation v¡jJl occr¡¡" The most exl.rar¡stive work on this system, d.ealirrg with the Hammet s'-constants1t}9t116 ind.icates that the sily1 group may both dor¡ate and. withd.raw electror¡s from an attached, a¡pmatic ring, d.e¡ænd.ing upon the envircnrnent. Hence, on the appnoactr of nickel catalysts to the phergrl-substituted. siLicon atom, d.onation of electrons from the catalyst to the d. o¡bitals of silicon wou1d. facilitate withd.rawal of back coo¡rd.inated. electrons to the phergrl rir¡go Thjs wor¡lil Íveaken the silicon-carbon bond. even furthert naking ejection of a pheryl an:lon more likely"

the results shown in Lable IV also provj.d.e d.iscussion for this mechanismo Accorrd.irrg to Maxted.nl' g"**rir:n, tinrand. Iead- cor¡- por:nd.s should. aII und.ergo chemisorption by donation to the catalyst of eloctnon pairs from the penultimate 59, l+jl, and 5$ oubitals respec- tive\r. However, it is signi-ficant that tetracycl.pherylstannÂne showed. no detectable aleavage under these cond.itionso Âccord'ing to \4Þxted'r s *].,6- theories, there is no reaslon vrhy this compoirncL shoul-d' be stable to eata-lysts" Tetracyclohe,rylplunloane was cleaved und.er these cor¡d'itions to gÍ-ve good. yield.s of cyclohexaneo 'the On pr"esent scaniy lanowledge of physical d-ata of the organic d,erivatives of germaniun and. tin, ít is d.ifficult to assert whi¡h mecha¡ism wå1} openateo BoncLs j:etv¿een cazloon to other Group I[b e1e- ments become weaker as the stability of the ùivalent state inoreases dovn'¡ the Groupol11 ,n12 Hovrever, there is stilt evidence from the d.issociation constants of 3-substituted. aromatio acid.s to shov¡ the possi- bility of rf-bonding between trimethylgerrq¡rl, tri-methylstanr¡yl, and. 2 tri-urethylplurrbyl groups rrith benz"rr" lhis v¡or¿ld. suggest that "irrg".trf the outer rrempt¡y't d. oròitats of these elements could. stiJ.I be used. in cherriso4rtion to catalystso Ehe existence of marqy five cocr¡d.jnated.

M3 t'11)+ stanrgrr compo,.urd.s arso supporbs this e'çridenceo In contrast to thiso it has been sho'wn ti:at tetra$:,er-yiplurnbane, tetrapher¡yfstar¡nane¡ and, related compound.s nay be decomposed to benzene and. the parent metal by the action of hydrogen under higþ temperature arad. pressur.e, both with and. without the ai¿ of metal catalysts "75076t'115t116 and. have al-so shsvm that alþl- substituted. tin conr- Gershbein Ipati "tt74 pound.s may be cleaved. by L¡yd.rogen, thougþ higþer temperatules are necessary on moving up 'che gncup and. for alþI compor:ndso No r'¡ork appears to have been carried. out on germanium conporrntlso In conclusion, it is apparent that the ease of cleavage of

Group ffb-organo bonds vrith hyclrogen increases dorvn the BrcuP¡ ar¡d' also that pher¡r] d.erivatives are :æmoved more rearlily than a1þ1. thi-s is -+7- cor¡sistent with the results shown in Î.abIe ItI. llTre compor¡¡rd.s of car{¡on and. silicon, and. possibly germanì.r:m are consid.erably stable as cleavage of these compor:nds by l¡yðn:gen without catalysts has never been reported'

.4,ryI-silicon compowrd.s may be cleaved. by the mecha¡¡ism d'escribed'. Cos¡- pound.s of elements below silicon are apParently cJ-eaved. by Liyd'rogen witfi increasirrg ease d.own the gr^oup, as weIL as by catalysis as desoribed' for silicono Ås lead. compourrd.s are the most easily cleaved-, tetracyclo' hexylpfu:nbane gave good. yield.s of cyclohexane by hyd¡ogen attack only" Tetracyclohexylstannane, and. aIþI d.erivatives of compor:nd's above tin were stable probably becau,se the tem¡nrature and. pressure were not higþ enougþ. The phenyl d,erivatives of genranirrn and. tin cor¡l-d. possibly have been oleaveil by both nechanisr¡so

*** TiIJNWIIWJ"TE -.\8-

1- General

Gas chronatogr-aphic ana-lyses ïyer¡e carried. out either with a

Griffen Georgp\n.Poco apparatus lvlk. II with a 6ft. x o"25 ÚL colwnn a x packed. with Îmbacel (coated, vrJ:tin 1úl tricresyl phos¡ùrato) "td Jtt. O.25 ín. co!:mn ¡ncked. with crushed. fire briclc (+O-eO mesh; coated' with a Perkin- 5úl Dow Corning Higþ Vacuun Silicone grease) in series, or with

El¡ner mod.e] 8OO gas Chronatograph equipped. eÍther w:itb' a 1?fl" x 0o125 b polyester of colr¡nn ¡acked, with Chromosorb W (coated. v:-ù JelL succinate butane d.io1) or with a 'l¡ft. x O"25 in. colr'¡nn of Ch¡pmosorb 1T (coated' wLti}^ 2(' Ucon oiJ. O"1 IB-550-X). t

ultraviolet spectra urere neasuned. v¡'ith a Perkj¡l-E1¡ner model

137 W speotrophotometero

Infrared. spectra were determined. either w:lttr a Perkin-E1mer Ir¡fracord. 1JJ or with a Perkin-El¡ner 237 spectrophotometero

Microa¡ralytieal ^6¡aþses vrerle canried. out by the åustralian Senrice, Melbourne.

2. Solvents Cour¡nercial díoxan was purifS-ed. by refluxing w:ith Ìryd'rochloric acid. and. d.rying with potassium hyôroxid.e accorrd.ing to the method. of Vogeffl: and. d.istj.Lled. thnrugþ a jacketed. fractionating column (Z x 6O cmo packed' with single turn gtass helices and. equipped. with a variabl-e ta-l¡ce-off total cond.ensation head.; reflux ratio l:4), collecting the fractj'on b,p" 10.!or'1fo*ra to be homogeneous by gas chromatograpl¡y). Metha¡¡ol +9-

6B was purified. by d.isti]lation from sod'ir¡n kgrd.roxid'e"

3o Catalvsts prepared' from W-1 ,2 W-5 15 and. \','-l Raney nickel catalysts lvere ,ri.¡s!-aluninium atloy (tzt; B.D.H.) according to tk¡e literature nethods. The prepa¡ation of d.egassed. Raney níclcel was sligþtIy mod.i.fied- from the published. method. for ïI-il S.aney niclcel.6 The mixtune resr:lting from the ¿issolution of the alIoy vras kept in a boili:rg vrater*bat'Ïr for

one hour, d.uring which time the volume was kept at approximately 75O rffi by ad.d.ing watero The water-bath was then allowed. to cool to æom temperature while tlre flaslc containing the cataly5! ryas i¡ome::sedo After ten hours, the catalyst was washed" by d.ecantation with ten 100 mI po:r- tions of urater, and. the catal¡lst transferred. with a small amou¡rt of .¡vater into the apparatus d.escribed., wh:lch was then j¡mersed in a cold' wate¡ubatho The catal-yst was then kept at l+0o at 15-25 ¡nm r¡rrtiI aIL water

had. been evaporatedo fowazd.s the end. of this prccess, the pressure in the apparatus rose for a shoyt ti-r¡e. Firralty, the temgerature of tbe v¡ater-bath was r¿rlsed. to lOOo and. kept at this temlrer'ature for J hours. Raney Cobalt was pr€pared from cobalt-a¡minium alloy (tz1;

Fluf

4o General Reaction Condi.tíons

(i) Hvdrnoenol \rsle \r¿'l th ltr* 7 - \4r*5 - nrt [¡-1 Ranev nicllel" and. Ranev @o - 1¡l-7 Raney niclcel (prepared' from 12J g of a1Loy) was freed. of water by uashing first with methanof (À. x 1!O mI) an¿ then with dioxa;r. (3 x 1!0 m1). It was th¡en trar¡sfered' v¡ith ùio:ran *50-

as d'escribed' to a flask which carried a jacketed. fractionating colunn forthepurificationofd'ioxan.[hecondenserofthiscoluÛlnvfas linked'totheatmospherebyvrayofatraPcooledwithsolid.carbon d.ioxid.o. The starbir¡g material (0.018 mo].es except where otherurise mad'e up to about sta-ted.) was ad.ded to the c,.ta;,yst, the total volume heated. under refluxo after 25O \ù, by ad.d,ing dioxan, and. this nüxture (reflux r"atio 1:1O) z one hour, the foltowing fractions were colleeted' (") 1olo' these (.) bopo up to 65o i (u) b,p. 65-101o ¡ and' b'p" by gas chroma- fractions were analyzed- qualitatively ard. quantitatively In experi- tograpk5r using suitable stand.ard. mb'-"cures for calibration' anê the nents with phenyl d.erivatives, fraction (a) contained rptha¡ro1 corbjned' wit¡ the bìÀlk of ber¡zene arrd. cyclohexaneo Fraction (n) was dioxan' lratert cond.ensate from the cold' tT¿¡P', this mjxture consistecl' of (c) t.'ras anrl s¡na1-l quantities of benzene and. cyclohexane. Fraction arrd' rrioxar¡c DetajJ-s of the analysis of pnoducts other than berøene hor:rs, the reaction cyclohexane are given belovro after heating for for:r with hot d'ioxa¡r (5 x was stopped., the catalyst filtered. off and. washed. j:red. and' v¡ashings ïYere 50 mI) o In some experiments, tb co¡rb filtr-ate material and' freed. of dioxan and. the residue exam'ined for starti-ng further prod'ucts as d'esoribed beIow"

/::\ o- Aftercooling \¡¿,, r¡nder vacuun, dioxan thè d.egassed. Raney nickel (fro* 125 g of alloy) pump vÚere closed' åfter (ZOO *f) was acld.ed. while the connections to th.e -51- the oatalyst was thoror:E¡h}y wetted. wj-th d.ioxan, the starting ¡naterial (O.O1B moles except v¡herr: otliez'wise stated') and. d-ioxan (to Eake the tota-l r¡o|¡ne up to approxirnatey 25O *1) was ad.d.edo the mixture Ìvas then:sefluxed and. d.istilled. as above, except that all material-s boiling below 101o luere collected. in one fractiono fhese mjxtures were too wet for accurate ana-lysis by gas chromatogzaphy described' it (i)o Instead, the concentration of benzene 'lvas determ'ined. by ultravi-ole'c absorptiont and. the ratio benzene-cyclohexane v¿as deterrnined. vrith a ga-s chromatograph equipped. with a flame ionizati.on detsctoro The residues Yrere urorked' up as d.escribea in (i).

In some experi-uents, meth.anof (10 mI) vùas ad.ded. to the reaction nixtu¡re before reflh.xing ì/vas conmenþed. In these cases, the fractiona- (i) tion was as d.escribea :n "

(¿ii) Hydro ses at room te¡nperatl¡re' The su^spension of oata- þst in a d.iorgn solution of the starting naterial (totat volume approxi- j¡r apparatus r:ateþ ÀOO mI) was stirred. at room tempe¡ature a sealed' which tvas conrrected. to the atmosphere by a trap cooled' with soLid. carbon d,j-oxid.eo AfterJ..8 hours, the catalyst was filtered. off and. v¡ashed. w:ith col¿ d.ioxan (j x 50 rù)o The filtrate and. washi¡rgs wore conbj¡red' v¡ith the cond.ensate in the co1d. tnap¡ æd analyzed by d'istil'lation as d'es- cribed. unaer (i). -q?-

E^ Other Hvdrocer.ol.l¡ses.

(i) When tetra'-fo-to1y1)silane v¡as treated' v¡ith TJ-7 Rarrey nicke]- in d.ior:an containing :rethaniolo a}I met}ryl- cyclohexaræ ar¡d. part of the toluene d.isii|led over together vrith methanoL and- d.ioxan" this rnixtune was anaþzed quantitatively by gas chrornatograpÌ5t. The residue of the d.istj-Llation r'.a's freed of the cata- lyst and. the filt¡ate d.istitled. at 1oo mm Pressure, leaving a solid. which vüas main\¡ starting ma'beriatro fhe toluene in the second ùistiliate rrlas esti¡rated. by its ul-traviol"et absorptiono In the experiments v¡ith Tr[-7J Raney nickel ca.talysts in tbe absence of nrethanol, water (tZ mf) rvas added. after tv¡o hours of heating. Al] the rethylcyclohexane distilleil belovr 'lotror together with væ-ter, d,joxan an¿ tolueneo The yield. of toluene r,vas d.eterriined. spectroscopically, and. the ratio toluene-rae'chylcyclohexar¡e was d'ete¡mined. by gas chroma- tograpþ. The catalyst was then filtered. off and. v¡ashed. w:tth boiJ-ing benzeneo The filtrate and. vrashings v¡ere then d.istil.led. and. the toluene estimated. by gas chromatogÉPh.f"

(ii) T"t""-(p-@" - lo a sorution of this silane (o"ot8 moles) !¡ aqueous sod.ir¡r'r bicarbonate solution (5%t f!0 rú-) 'ras add.ed. W-/ Raney nickel.(f"o* X?5 g of alloy) whj-ch had. been vrasheC only with water. The nrixtuFe tïas refii.:xed for four hou¡s lt'nile bej-ng stirreôo The hot raixtu¡e v¡as then filtered', and the catatyst v¡ashed with hot aqueous sod.ir¡n bicarbonate solutiono The combj¡red. fj-ltrate and. washings

and' v'¿h:ite vre¡e acid.ified. with concentrated. hyd.rcchloria acid', the -53- precipitate collected." The agueous filtrate v¡-¿s continuously extracteè with ether, and. this extract evaporated. leaving a white :¡esid.ue. Botlt

solid.s wene extzacted with warm water to yield. a rn-ixtu¡e of cyclohexanois ard benzoic acid,s (+.5 g) id.entified. by paper chnomatog"tpt4¡'118

(¡:i) lriphe¡rylca.rbinol." - the carbinot (0"018 rootes) vras hydrogen'-

olyzed. vrith \\t-J Raney nickel in d.ioxan as d'escribed. in 4(i). Distilla- tion yield.ed. on\r metha¡rol and. d.ioxan. Recovely of the resid-ue gave a thick oil which crystalLized. fbom petroleum ether (b"P" 3O-40o) as colourless prisms of tripherSrlne'chane (+,2 g¡r rop. 9to (tit.tr19 92oc).

6. a

(i) Tü- r meshylsilano and. d.iphenytd.imgthylsilane" - The resic.ue from .'Yhich these reactions was recove¡eiL as an oil (ca. I g) on ¿istillation failed. to separate into Pur€ components. Gas chromatograplsr showed' that the nesidue obtained. from ðiroethyld.ipher¡ylsilane contai¡¡ed' at least eleven components; one of these (approxi:irateLy 3Ø." by arrea) had. the retention ti¡ne of the starting materialo the residue of this èistiIla-

tion (0"0L g) vnas recrystalLizeð. from hexane to give colourless prisns gave a (O.OZ5 g) , m.p" 276-2800 " Ad.nri-:¡-ture with tetracyclohexylsilarre m.p.278or md the ir¡frared. speetra of the two samp1"= vt'ere super' imposable. ' The resid,ue from the experlnent with pher¡yltri-rnetÌ¡rlsilane +Lr

@" I g) was similarly exan¡-ined.o Eight volatiJe components were d.etected. by gas chromatography, starting nrateriaf Q+Cf/ù and- cyclo- he4yltrirnethylsilane (Mò v¡ere charaehertzed. by their retention ti¡nes on\ro Tetracyclohexylsitane (O.Of 5 g), mop" 2780 r'¿as identjf ied' by its infrared. spectrulur"

(u) - In several experi:nents with d.egassed Raney nickel which had- been carried out in the absence of methanol, the spent cataþsts were exhaustively T.he crude products wer"e extracted. '¡uith benzene in a SoxkiLet apparatus. chrcmatogralùred. on silicic acid. using petrolerur ether (b"p. 60-801 and benzene as eluants. phergrltrimethylsilane (cata\rst extracts fronr two experi¡nents

were conbined.) gave starting material (0"1 g) (id.entified. by íts infrared- spectrum); bipher¡rf (0.085 e) (aiæct comparison), ard. d.iphenyltetramethyl- disiloxane (0"t5 g) (infrarea spectnrm). Cataþst extracts from two experjments with ùimethyldipher¡yI- silane wer€ combi¡ed. and. si:nilarly worked. up to give biphenyl (0.14 g),

and. fractions showing strong absoqption at 900, 1O2O-112O, 1257y 145A¡

J40O and. ¡800 cui-1. tripher¡ylsilarrol (two experirnents) gave biphenyt (O.n'î g) an¿

b¡rcwn mjxtures lvhich could. not be setrnr:ated by the above prooedunes' The residue of two experiments with ùlpheqyltetzanetksrld.isiloxane

(z"O biphenyl (0"075 e) gave starting uøterial e) "r.d' ' -55-

f,etraphertrylsifarre (one .xperi:nent) gave biphenyl (g.1B! g), tetracyclohexylsilane (O.Of 9 g) (infrarea spectrum), starting materi¡'I (0.047 g) and r¡¡id.entified yeIlow matter"

I r.1r-, Methane from phenyltri¡nethylsilane,. - Pher¡fltrimethylsilane (2"7O e) was treated vdth lJi-p Raney niclcel in boiUng dioxarr in the absence of methanol while a strol'¡ strean of carbon d.ioxid.e rras ¡rassed. througþ the apparatus" lhe gas flowing fborn the cold. trap v¡as collected i¡ a gas burette filIed. vtztin )'{l aclìleolrs potassii.un hyd.r'cxid.e solution. The evolution of gas ceased. after six hours refluxirrgo The gas (1100 ml at t5o/740 *) was id.entified. as rethane containirg traces of v¡ater and' carbon d.ioxide (infrared. spectnrn) " the approximate yield. of rrethane r,¡as theretore 1O1J nrl at S,.T.P. (W)"

@" - After having been used. in the irydrogenolysis of tetrapreraylsi-Lane, \¡I-7 Raney ni-ckel cataS¡rst was d.issolved. in d'ilute þ¿rochlorio aaid, the resuJti-ng nrlxtur¡e was filtered. to give a d.ark- brqwn residue (1.1 g)" Continuous extraction v¡ith be¡rzene gave a brov¡n solicl. (O"72 g) o which on chrsnatography (sÜ.icic acid) gavet besides tetraphenylsilane, yellow and. brov;n oiþ fractions which were not id.entified." The ber¡zene-insoluble inatter vras further extracted. v,rith ethanol and pyrid.ine, but orrì-y t:'ace amounts of ozganic extracts wel"e obtai¡red" The residue (O.lL g) r'¡*= arøIyzed. by X-ray fluorescence by Dr. i{o Norrish and. found to consist of silicon d.ioxia" (lo7ù, nicì

çZf%), alumi-nj.wrrand. other elementsn This acc.unts for apprcxi-rnateþ -rÞ3

\Cf/" of sj.]icon introd.uced. as tetraprer¡y1siJane.

7o Sta¡-bi¡¡r Material"s. The followj¡rg compor:nds v/ere commercial santples which were

used. without purification: siU-con tet¡'achloniae (n.D.H.), methyl- trichlorosilane (n1uX", purum), dirnethyldichlorosifane (nfr,:ra, pun-r'n) , p¡4g-d,ipher¡yJ.tetramethylsi-3-oxane (F1uka, pun:m), triphenylmethane (ntul",

pu¡r:n), germanium tetracÏ¡-loriao (Ftut

and. lead. ùichloriôe (S.o.ti.)o

fhe fol]-owing compour:d-s yüere prepared. gþ the correspond.ing

organo-U.thium anð. pr:rified. by stand.ard. proced-ures: tetra- "u"g"r.t"83 ¡ùeriylsi:.ane, m.po 235-236o 1rit"B2' mop" 236"E-zll\ ; tetra-(¡-tolyr)- sj-Ianer ilopo 251o (Llato12}r121 ,122 rrope varJf between 22Jo arß. 255"5o)t 25 (tit"1 61"5-690) d.imethyl- methyltriphenylsilane, mopo 67*6Ba ^opo ; aipher¡rlsitane, b.po 1+5o/2o r* 1t:-t.I24 b.p" 176-178o/¿+-5 nm); arxi. trimethylphenylsilane, bopo 82o/22 t 1tit"125 b"po 171.5o/7+5 rlrrn)" mop" 283-28¿rt (Iit"126 2%,5-285"!0) or." p""- Tetraphenylmethane, ^op. pared. fronr trilùrergrlro"th.rr"¡X26 gemranium tetrachlorj.d.e and. phe4yI-

magnesium brourid.e gave tetraphenyJ-germâre¡ llropo 226o (Lirto127 *"po

225-226\, and tripherrylgerrnanolrmopo'!Jl+o (rit.1'8 r.n. l54.zo) ; cyclohe4ylmagnesir:m bromid.e with tín tetracLr,lorid.e gave tetracyclohexyl-

stanr¡ane¡ rlop. z53o (tit"1'9 *,r.21+80) and. with lead. dichloride gave 'üeüracyclohexylplurbârrsr rtrrp. tr¿P-160o d.. 1rit.91 u.po lJO-1600 d."). 47*

(i) @' - A solution of chlonotriphenylsilane (10 g) in acetone (lOO ml) rvas ad.ded. slowIy with stin'ing to an aqueous solution of sod.ium bicarbonate (ZCO ,rL ; 51")o f.fter ten nrj.nutes the product was fil-tered. of,f and. crystallized. from ligþt petroleumo (b.p. 6O*800), to give colourless needlos of tripher¡ylsilanot (gl%) ¡ ffioP. (l.it n55o; 150"5 151.5o). 15lo "13o'13tr ^.n. -

(ii) @" - TripherSrlsiJ-anol (> e) and' etha¡rol (t¡O ¡nf) v¡ere ¡effuced for four hourso lhe cnrd.e product, which was precipitated. on removal of part of the solvent, vras crystallized from ethanol to give colourless pr5-sms of etho:qytriphenylsiJ-ane (65/') ¡ lucpo

' 65-6Lo ç:rit"132 n"p. 630).

(iii) @. - This compor¡nd was prepared- by the method. of Gilman an¡ Oit^"133 A.s experimental d.etails are not available the follovri.ing procedure was used.:: tripher¡y1silanol (fO g) was refh¡ced- with formic aoid. (t5O mf , 98-1Wo) f or 24 hourso lhe cn.d.e product v¡hich separateô on cooling wa's recrystal.lized. from acetic acid. to give colou:¡- less plates of hexpkrer¡yldisiloxane (64С lrlopo 221-2220 1lit.lJL *.p. zzl*zz4.5o).

130 nethod. Dilthey ar¡ô Ed.uardoff (iv) +_Dipheny]silaned,iolo - Ihe o v¡as moèified. as foll-ows: an ethereal solution of pher{rlmagnesiur: b¡r¡nrid.e (J mofes) and. silicon tetrachloride (1 mole) r¡vas reffuxed. for -j8- eight hourso fhe resulting nrixture vfas then carefrllly reacted' with excess sod.iun bioarbonate solution (5%)o the prod"uct rvas extracted' with ether an¿ cr1¡stal-lized from light Petro1ewl (boP. 6O-eOo) , to give t colourress need.les of ùiphenyrsilaned.i oL $ryò, úopo t¿*go (rit .13'l '135

E6 üiopo varx, between lt8o and- 1lu8o).

l',r'f Hexaohenvlcvcl-otrisiloxaneo - Ihis l'ras pnepared' ín 7Vá yielil from dipher¡y1silanediol by the method. described' for the pretraration of hexphenyld'isiLoxane" Hexaphen¡'Icyclotrisiloxane crystallized' from aceti.c acid. in colourless plates¡ toP. 188*í88"50 çirit.136 m.po 'l9Oo).

(Fotmd.r Cr 73"Qi Hr 5"3i Si, '!,n.7' caLco tor caë3oOft¡ z Cr 72'7;

ÍLr 5.1i Si, 14"4ù o '

("i) 3@-(p-"""'Ìrp¡:ph"'"V4)ri1"ttu. - This cornpound' has Seen d'es-

cribed. by l'{u u,rrd. Yr.1J7 4^s this neference was not avaj-Iab1e the fol}oY¿'-

ing procecì.u¡e r¡¡as d.eveloped.a Finely po,"vdered. tetr"a-(-rrtolyf) sj-l-ar¡e (f d rffas suspend.ed. in a mixture of glacial acetj-c acia (ZOO nir 4,;R.') acetic anlgrdrid.e (60 un, &.R.) vrith sulphuri,c acíd' (6 nf,. 94ù' The fLask containing the mixtulÞ Yras jmme¡sed. in a large waten¡bath the tem¡nrature of which vras kept at J0 I tro. Ch:¡omium trioxid.e (ZO g, A.R.)

was ad.d.ed. d.uring 60 minutes lvirile the mixture Ìvas being stÍrred." After

the ad.d.ition.v¡as completed. stirring was continued. for one bor:r at JOoo ì¡ras (5OO g) sti¡red. until The mixture then poure¿ onto crushed ice "nd ó9- theicehad.melted'lheye}lowprecipitate]JvaSco]lected'arrd.washed. with ice-tvatero The crud.e prod.uct '¡ças ùissolved- in aqueous sod'ium bicarbr¡nate solution, freed of insoluble mattero Md reprecipitated' with hyd.rochloric acid.o The pr"ecipitate Yúas reclystallj-zed. fro¡n d.ioxan to give colourless plates of tetra-þcarborqyphenyl) silane (6y/")¡ ]rlopo

t+OOo (Iit"tJ7 *op" iggo)" (Found.¡ C, 65.2i H, lr.2; S;í, 5"6. Galco for ôr6flrOOBSi : C, 65"6i H, 3.9; Si, 5.5?;)'

85 (vuj letracvcl-ohexyl-si}êtteo - The metl¡ocl of lianazas:nJ; anci lalcakusa v¡as mod.i.fied, as follorvs: a solution of tetra¡irenylsilar'e (10 g) in methylcyclohexane (5OO r.,1 ; free of cyclohexane) was kSrdncgenâted' in the presence of ï{-7 Raney nickel @. 5. e) at lOOo ar¡ô 15OO :la/fnz ot Ì5rd.rogen for 12 hours vrhile bei-ng magnetically stirred' The resid'ue l-eft after :¡emoval of the catalyst and. solvent was erysl,zLl-)'zed' frcn, hexane to give coLourless triclin-ic prisrns of tetracyclohe4ylsilane (ll%) t (rito85 zlg-zalo)" (Foun¿: c, 80oO; H, 12'2o calo' m"g. 283-zg¿fo ^on. for CrUH*Si : C, 80.0; Ht 'lT.Yo)o

(viii) C.yc-l.oheävltrimethy-l-silqne. - A solution of trimetÌryIphenylsÍl-ane G ù in methylcyclohexane (50 ml) was hyd.nogenated in tÌæ presence of, r¡t-J Raney rrickel (e e) at lOOo and. 1800 ¡1U/fnz of hyclnegen for tA hor¡rso

After removal of the catalyst , 'Gine fiLtrate '¡ras freed' of methylcyclo- hexarre and. lsu¿er boiting materia-ls usi::g a spinning-boncl collunn" The residue was redistjLled. to give cyclohe¿y1tri:metl¡rtsilane (ll:/") ¡ bopo 67-6go/ZO o* qtit.B5 b"p" 67;,9o/ZD ,r*)" fh.e infrared spectrum of th:ls -60*

85 product was id.entical with that published by KanazashÍ and. la}cakusa.

(¡r) Eæ(n-@" - n-He¡yllithium (0.25 mores) was treated. with silicon tetraohLoride (0"06 mole) in etk¡ero After eight hour.s, the mixtuïE l¡yas r,¡orked. up to give hexa(e-hexy1)d'isiloxane, bopo

16o-'t6zo/0.J run (rit.1]8 b"p" 223-z?5o/+.5 ß,n) ín )+1% yield'" The infra- red. spectru¡n shor¡ved. a bz¡oad. intense band. at 1100-1010 cm-tr eharaoteris- tic of siloxane 1i¡1teg"s.86 O¡bher strong peaics occurred at f iO0-12O0 and. ll+20-1460 cm-1. CITA?TNR TT lhe Aotion of Baney nickel on anili¡re

and. related, oompound.s. t/,

aniline has been utior#B'5)+'6te66 to form cyclohexyLami-net ananonia, d.i cyclohexyl amine, N-cyc lohexylanil ine, d.iphenylamine, and. ear¡azo1e by the action of me'ba} catalysts and. hydlogen (see Introduo- tion). the first aim in the ex¡Ioration of this ¡eaction was to d.ete:mulne the cond-itions I'¡hich gave rise to best yield.s of these prod.uctso lhis was d.one by tr,nro method.s' A.niline, cyclohe4yle'mi¡e, and. a mirtune of the two, vrere systematica3-Iy surbjected. to both Ïü-7 and degassed Raney nickel- in a sei'ies of six experiments, anrÌ the yield.s of all p::oducts dete¡rnineå in each caseo Duri4g some of these reactions, small samples vrere taken frorn the reaction at various inÈel"- sa1s, and. these were jJlvestigated. by gas chromatogr-aphic analysis to d.ete¡rnine ar¡y variations i-n concentration v¡ith re¡action time of each i.:nùividual. producto Beaction cqnditions were sjmilar to those used. by Jackson 20 an¿ Sasse.Jo t¡e a.mi¡¡e (approlimately I nole) was ad.d.ed. to the catalyst

(from 125 g of alloy), an<ì. the ¡nj:ctr¡¡e refluxed. for l0 hours v¡ithout solvent. Tlre reaction terope::at'ures consequently varied. consjd.erably from one reaction to anotlrer and. even d.uring the sarne reaction the refh¡c temperature grad.ua-lþ rose" With the exception of th:is one variable, the reactions and product analysis (carried. out by'gas ch:rcmatography) were alI id.entiea]. with one another.

f,he results (faU:e V) shov¿ed some significant trend.s" In aIL cases w-ith both 1'¡-J and. d.egassed. Raney nickel, no cyolohexylarni-ne'u¡as d.etected j-n the final p:rod.uct ana1ysiso From this it is assumeo. that TABI,E V" (.) Reactions of aniline -Ø:¡-. =!}E

Compound"s Catalyst Ani- Dicyolo- S*cYclo- Diphenyl- Garba* Other lir¡e he:ryI- hexyl- arÐrine zole ProËlucts amine ani"litre

Anil-ine Tr-7 47 trace 16 Nt.n(zo); g- tolu;iaine (Z"O)

ïl*7J 60 11 I o¿+' 0"6 o-tcLuicline - Tl.Ð; i-naoíe (trace) (I tu Gyclohe4ylamine lT-7 l+"5 2o9 40 r\8i5, (5r). ¡

lM-Ë 1 1.0 l+5 0"5 1"+ r,ür3 n (56) .

A.niline + c¡rclo* W-7 I traoe 47 o*tc1uid.i¡re hexylani-ne (a) (trace) (¡) rr*7J trace tr:ace 64

N-cyclohe4y].aniline T$-7J t-race trace 71 lo0 1.2

(Ð Equimolar quantiti-es (u) Reaction carried. out in:qylene (.) ftTracer! means d.etec'bed. by gas chnomatogr:aphy ( < 1%) -6j-

cyclohexyla¡nine (forued. during the reaction or ad.d.ed. as starbing naterial) is unstable r.md.er these cond'itionso As cyclohe:qylarni-ne is the main pnrduct vùich aniline corrld. be expected. to fo:m by hydrogena- tion, it presuryrably vrill be one of, the initial prorlucts of the reac'bion,

ar¡d. j-rnrestigation of its reaction path vras essential"

Cyclobexyla4-ì^ne may undergo one of t'¿vo reactions; Crehyd.roger¡a- tion to'a¡¡Í1ine, or parbia¿ C.eÌlyd.rogeriation to cyclohea¡rIid'ene jn:ine (27)" Thj-s ketinÉne interneùiate has never been isolated., but by analogy with other reactior¡s of nitrogen oompowtds with Raney nickel, it could. quite *¿senablJ¡ be expected' to forn, (Sctreme 8).

'{f o + o* }ü{2 2 2 J J:Ni Ni

-fl.

¿+ NH .t_ Ni 1zt) S,ch,me 8.

fhis lcetj¡¡ino wou}d. be expocted. to be very reactive, anfl even

jJÎ it does not wrd.ergo further reaction, worrld. hydrolyze r¡r¡der the work- -6ftF up cond.itions to cyclohexa ron" 16S vÈrich was d.etected. i¡r snrall yield's l¡r J"ckson.Jh Also, Debus arrcl Jr:nger"163 who ad'd.ed. vrater to the r€âc- tion (facilitating hyrìroJ,ysis of aW imine groups), isolated. consid.erable quantities of cyclohexanone and. cycS-o}rexanol (fomea by furdrogenation of, oyclohexanone). Consequentll¡ it seems likeIy that cyclohexylid'ene imine is the main intermed.iate i.n the reaction of cycloheryIarnrine wj.th cata- Iystso

Imines have been shoryn to und.ergo ad.d.ition to primary amlnes j.a exactly the same way as tLrey ad.d. to $rater to fo¡m ketones.65 Hence, cyclohexylid.ene j¡ni¡re rnay either ad.d. to an amirr,e, t¡rd.rogenate to cyclo- he4rlaraine, or dehyd.rogenate to anilineo If it ad.d.s to a primaq¡ ami-net tkrere are two possibilÍties; ad.d.ition to aniLine or to cyclohexylanine, (sctreme 9).

}üI 2 -NH'*3 - N

H (¡t)

}.EI 2 -tEI- t> N

H 0z) e^'--.-s Cl vu¿¡(r¡¿\, / ø

ot 4{iccording to Debus and Jwrgers, the reaction þath proceed.s -55-

cyclohexylanLine vj.a ad.d.ition of, cyclohexylam:ine to give }-cyolorrexylid.ene d'icycloherr-y1- (51) which was not isolatecl, but c¡uicicly hydrogenatod- to other hand'' arnlne as the first prroducto Jackson and SasseJS o" the eyclohexyl- postulate that eitlrer azrifine acÌd.i-bion is npre irnpor{ant tiran (J2) rras not arnine addition, givi:rg N*cyclohexylrC.e::e aniline v¡hicir (zgu) that the isoiate¿ but 1.y¿rogerute¿ to lÞcyclohex3'lanilina , or j¡rte¡rred.í ate (31) vras d.ehydrogenated. in¡ne¿iaiely to $-cyclohexylaniline i',"o1)n as the main prod.uct in this reac'r,ion, ¡t.ther than d'icyclohexyJ'am 1\s it has roeen shorr¡ that strÐrrger bases aàd preferentially would' be favourecl to i-¡nines ," ,, would. be expected' that cyclohe4ylamine by a further to the weaker base, aniline" I{ov,ever, tlois is cornp}icated' factor in the availability of each of these primary a¡nir¡es' Gorrsequently' should' operate, t'he pre- it v¡ould. be erçected. that both reaction paths of aniline dominance of either d.etermined. by the relative concentration or cycloherçylarrine jn the reaction mjxtureo InspeotionofTa]¡leVshov¿sthatani].inewithSoru¡1þland d-icyclohexyiam'ine' \',I*Ë Raney nickel gave no rrore than t¡ece amowrts of d'icyclohexylami:æ this " jnd.icates that r:nder these :c¡eaction cond'itions, is either not fozzned., or if, ít is o r"ær:-ld' be efficiently del5rdrogena'6ed' gave better to !-cyclohexylanilino. ¡-ruil-ille witÌ: ¡II-7 Raney nicJcel tl:'an r''r'ith d'egassed' yields of $-oyclohexylaniline (ühre mai' prod-uct) of starting mai;eriai catalys,cs, fr.om v¡hich a large;. propor+;ion "''e's reco./ereèoÏtisasswed-thattiiisissaused'byihehydr''ogenrichlL=-7 catalysthyd.rrcgerøtingmor.eanílinethantheTl-7Jcata\yst,giving €t)t){ grcater quanti'cies of cycJ-ohexy3.arnine C.uríng the :reaction. Cyclo- hexyJaur.ine is cornrerbed. to ihe jsj-ne, and' as there v¿ouLd be a much larger concentration of aniJ-ine than cyclohexyLanrlne present, the i¡r¡-ine wourd' be corn¿ertaa to (32) a¡:'rl' hence to $-cyclohexylaniJi¡re aE zp reporbed. by Jackson arid. $.s""oJo

Åd.ôed. support for this theory of j¡aine ad.d.ition corces from the reactions of cyclohexyl-a¡nine w'ith Raney niclelu Ïn titis eâset cyclohexyla¡n:j¡re on cor¡veïEiol:' t,¡ cyclohexylid-ene irnine v¡ouId. react preferentially vrith cyclohe>çrlan:ine rather than aniiine since the for:ner ïroul¿ be expectecl to be in large e:{cess, and. is a stronger base" Shese conùitions would pru'i:ably appzrc:rinate more closely to those of Ðebus az¡d'

Jr:ngers explain rrhy th.ey Ísol-ated. d.icyclohe4ylamine as the n65 ^¡rd.l-¡ould. urain prod.uot" AnjJine forrned. by d.ehyd.rogenation of cyclohexylalr:ine was isolated. in yields of onþ 3 to 4%, i¡ioioating that the concentration of this compounð during the reaction is insign:ificanto Dicyclohexyi- a¡rine lvas isolated. in this case, but onþ in yield's of 1 to Zil" Di- cyclohexyl-anrine which lvoul-ô be expected. to form flLrst, must be rapid\r d.el¡rd.rogenated. to N-cyc},ohexylaniline (as d.escribed. by Debus anci' Junge ,"63) v¿hich was obtained. in yield.s ovet )a-t/o" Best yields of $-cyclohe4ylanìJine lvere obtained. ],'¡hen an equi-molar mixtu¡e of cyclohexylaruine antL aniline vras treated. ','rii;h Raney nickel" In thj-s case, ít may be envisaged. that atte^clc may occur by both anj-l-i-rre ard. cyclohexyiarnine on the in-i:re" Preference for the firet of these is ind.i.eated. by the d.eteetion of on\r trace qr:antitÍes _67-

js of &icyclohexylarr-ine. lL possib3-e explamation for this fact that cycloherrylamine is cor¡suned. rapi-d.Iy by the cataþst, leavi¡g anilirie i¡r a gneater concentration. trn the reaction of cycloho4yla.ulne ar¡l aniline witþ degassed'

Raney ni.ckel, ani1iie d:issolved. in xylene was add.ed' to the catalyst fli-rsto v{hile the nÉxtr:¡e irefiuxed, cyclohe:ryIarn:i¡re vras s}ow}y ad'd'ed'- By this nþans, there could. never be a Jø'rge concentration of cyclo- heryJ,anr:ine in the nutxture, as it wor:Id. be converted. to the i¡¡ri¡re on ad.dition to the catalyst, and. rapid.ly taken up by aniLine to fom N- cyclohexylaniLineo This method. gave the best yield's of N-cyclohexyl- a¡iline (Ar{"), arrd. was ad.apted. to the preparation of a wide range of

N-a].lgrla ry1 a¡nlr¡e s . Basic volatile material from the reaction r'¡as co11ee1;ed. by passing gaseous produots through hydrochloric acid. solution" llhe yield' v¡as d.ete:¡Tined. by titration of the resulting solution with sod'ium tryd.r.oxid.e solutiono A,s no other volatile bases other than ammonia we:re e:4lected. from these reactior:^s, this titration r¡las taken as a measuæ of the anrnonia yield.. AJ-thougþ the gaseous products Ï¡eI€ not examined' in argr d.etail, it is felt that the assr'rnption should be reasuably accr:rateo The obsen¡ed values cornesPcnded closely to those expected' fr.om d.eamination and. forrnation of the secortda]y ¡rnineso In sr:rsnar]ro Ít appears that in the reaction of ani.J-ine or¡rer

R:urey nickel, the first step is hydr"ogena'bion to cyclohe4ylamine, vdeich ad'd's either is ôehyd.nogenated. to cyclohe4ylid.ene j-nine" This th':n to @ÞÜõ aniJ,ine or cyclohexylarLine, d.epend.ing on tþ'eir relative concent¡ations, to fo¡m either d.icyclol:.e4y1anine or .N-cyclohe4yiareilineu Dicyclo- he:çylaruine is read.iþ d.ehyd.rogenated.'co ll-eycJ-oi:e;eylaniSÍnen These conclusioì'r.s ar\: eonfirrned. by the arial.ysis of the sarnples ,r;alcen d.gring the reactiono The reaction of aniline with \T-7 }ìaney nickel is i-llustrated. in Figure 'î. AnjJ-ine is used up in the first ten krours of the reactioi:, but ¿r:i'ber';hÍs, tbe oatalyst has presunably ex- app::oxi* hausted. most of its þyd.rogen, an1 the hyd.r-oger¡atj-on ceaseso In rnately the same peri.otl., !-c¡cioher.ylaniline is fo¡rned' at a sj¡ailar rate, bui little d.ioyclohexylarni.:ee is for¿neå. thi-s ind.i.eates that most cyclo-

he:ryIid.ene imiì?e ad.d.s to anili¡-- and. is hyd-rogenated' to $-eyolohexylan:iline as postulated earliero Sma]I quantities @. 5/") ada to cyclohcxylamine

an¡1 are hydrogenated. to d.icycloìre:i¡Iam:lne, which is then mostJ-y dehy'årog- prod.ucts enated. to. N-cyclohexylanili-ne thnougþout the ¡çac'bion" The other from the reaction are benzene, cyclohexane, andg-toluid.ine, r¿of¡e of

r,ùrich have been rreprted' bef,ore" The reactj.on of cyclotr,exylarrine with TrV-/ P,aney niclcel (n:-gure Z) ís consid.erably d.ifferent from tl:at of anilineo In thls case, all

c),clohexylarni.:rle is r:.sed. up rapid.ly¡ ad simu-ltarreousþ the concentra- tion of d.icycJ-ohexylamine biriLd.s up to a maxj¡nrin after eight ho'urs" .Ihis is tleen slorvly converbed. at a stead.y rate to N-cyclohe4ylarri-J-ine thnrugþout the res'6 of the reactionn rvhich is essen-i;i¡]]y cornpleted- after l¡o hou,:s" very srnal-t quan'bities of anilíne aæ forned', but the yield's companecl to 'those of cyc1,,;,.-.ì;çene and- þeirze:re vfere consid.er"abþ increased.

in the reaction of anilineo ' 49-

loo

75

otn r{ aniline 350o Ei .rlo {J g +t É 0) Ê 'oo

Þs' ?s

o-toluidi¡re

Benze

0 Hotr¡s 10 20 to r{o 5O

FiquxÞ I Beaotion of a¡rlline rith TÍ-7 R.af¡ey nickel.

- -70.

100

oyolohexYlamine

75

û o J 'g 50

É .rlo .+t d ß{ .lJ É c) o 'oH (, 25 bc. Benzene and

dicyclohexylamine anlline 0 Hou¡ls t0 20 to lp 50

Flcurt 2 Beaction of oyclohexylanino with W-7 Baney nickel. - -11-

By a.alogy with pneviousþ Postulateil moot¡anism, (see Intro' cluotion pp.6-8 ard. rtf. Z5), t¡e d.ea¡rination of these prinrary aliphatior a¡¡ineô ooulcl be by eleot¡¡on d.onation frm the catalyst as shown in

Sohemc 10.

oo NI{ 2 H I --t, + Nä^ Nf Ç ')" ç Ni H" H.

*.5 Cyclohexane

Scheme loo

Ihjs meollanism is Ln contrast to that fon d'eþd'rogenation of oyclohe)rylamlne (ScUene 8) wh'ich is postulated' to pnoceed via lone-pair d.onation f,rm nitrogen to the nickelo As explaineil i¡r the Ihtroduotion (see po9), it is possibþ the eærry leve1s of the 1q¡6-pairs on the hete¡pr-atom whíoh clete¡mlne the ty¡n of ctreurisorption, and. hence the ¡reaction path. In arematio arrines such eÉ aniline, it appears that 'the rcst ch€misorption ocou:rE¡ by ci.onation of nitrogen lone-pair to ttre rriokel, (e.g. as shown by O-netl¡rlation arú' 2r2r-ùianlnobiptrenyl foila- tion,8). 1¡ith oyoroheryramLne, it must be assumed' that the rone-pair on typ of üro nLtrogen ls at as j¡¡ter¡rediary level in which either tJ2-

o¡enrisorption may oocur. This discussion ij very sPeculative hower/ert ar¡l an obvior¡s upthocl. to give a cleaner pioture of these ¡psha¡isms would be to stuftf these r€actions w'ith the aicl of eleotron spirl resor¡anoo

"poto.176 trhis cleami¡atíon of cyal,ohelrylanine has the effeot of reciucing tJre ytelcls of !-cyolohe:rylaniline quite appæciablJ in the reaction as arrl com¡nnect rith ttre yielit from the reaction of a mjxtr¡re of an:iline " cyolobe:qrlamLne with Baney niokel. Eourcver, with cyctohe:qylarni-net no other by-prod.ucts f,oræcl, and. this si-uptlfied, purtfication of the main p¡ocluot. Anaþsis of the reaction of a mixture of cyclohe4rla¡nine ar¡d. a¡rjline vfith TI-7 Raney nickel, (nigune 5) shows it to be a'mod'ification of the firsù ùro. ALI ttre cyclohe4ylamine was used uP in about six to eigþt hours. The a¡ror¡nt of clicyclohe:çylamine formed' ¡rês less than ha]f tt¡at ln the cyclohe:cylanine reaction (figrrre Z) r ana once again rlras

stead.iJ¡r ctetqrclrogenateat to N-c¡rclohe:rylaniline o Most aniline vras used up, eithor in actd.ition to cyolohe:rylidene i¡rine as shorrn by the large rapicl rise in !-cyclohocylarriline concontr:ation, or in lSrdrcgenation to as before, and was used' oyclohe4yla¡rino. -gfloluiafne was also forr¡ed.

I up dur{-ng the ¡¡eaction Í-n a sfrlrilar way to a¡riline" The fo:mation of g-toluidine yÍas noticed, onþ in reactions ritl¡ aniltne and. not with oyclohe)qyla¡ri.ne. It oor¡ld possibly be

formetl. by a upolra¡rism si¡rilar to that postu-Latecl for the fozmation of -7y

t00

75 N

üt (¡) r{ o E E50 ao Cyclohexano and. +t benzerre. fl +t ft b: o-toluicl.ine. q, t) F: o vô clicyolohe:ryIamirre. o s. d.. ayclohe:ryIa¡nine¡

anlline

a

b o 0 Hours lO 20 5o r|o 5o

Ficnr:¡e 1 Xìeaotion of anil-ine anÉI. oyclohe:ryIanirre with W-/ Banry nLckel. - -7F oa¡bazolc from !-oyolohe:rylanili*J8 (Sorrene ti). The source of the

H o

\Nå Ni Ni

H# *, + NtÍ IÍN \ 3 *5 2 Ni ßt) Sicheme 11 " netÌ¡yl group is obscu¡eo It nay be fo¡mrecl f,rom c¡¡clohexylid'ene i¡nj'ne whícÌ¡ coulil tgrctnoþze ancL lrydrogenate to cyclohexa¡rolo Ail'cohols have been shorvn to give oarbon monoxido on niokel catalysts, and' ttris carbon nonoxid.e is acisofbed. strongly to the netal ancl corrve*ecl' to poterÉia-l netlryl g"orrnu.'l '13'101 Never'üheless, this ¡reaction path appears rather lr¡volvect compared. with the offioienoy of ø-meth¡rlationr and' further investigation coul-cl possib\r reveal another pathwaf,o A,rolatecl pnoblem is the formation of i¡rdo1e in the reaction of aniline witÌ¡ W-Ë Raney nlckel, thougþ in very srna}l yields. The i¡¡ctole preoursæ is probab\r g-toluidino, whictr coulcl be nett¡rlated' to -75- o-etb¡rlaniline and then cyclizecl. to ind,ol".J5 Alterrrativelyr it cor¡-ld'

have been a bneakd.ovm pnoduct of oarb azoLe, but P^ao"1J9 has ird.icatecl and' tiut 1 r2-diethylindole is the maln product from this reaction, ind.ol.e is the¡¡efore an r.rnlike\y prod'uct. these reactions also show that ttre second.ary amines a¡re f,o:oectþ attack of ani.nes on the jmineo It has been suggested., t'ttougþ not general\r accepted, that ttre i¡¡ine j¡rte¡med.jate rny lSrdroþze to a ketorp. Ihis coul¿ then condonse with a¡r a¡uine fonring an anil which coul-d. þdrogenate to the secondary *oirru.ú (Sctreme 1z).

NIT 0 N

Hzo ' aniJ.ine --r-s

Tf N

Scheme 12.

.The gra¡trs (nigures 1-l) alt ird.ioate tÌ¡at as cyclohe4ylanui¡¡e

is consumed. in the reaotion, -the onþ compor.¡nd.s to forl. are d.icyclo- he:rylanine or N-cyclohexylanilino. Oyol.ohexanone wa.e not detected. a.g a reaction interrrecLiate, but was obtained in snal-l quantities in tlp reaction residuesn This i¡dioates ttrat the greater majority of ketimj¡¡e -76- adds cli¡eotly to a¡ni¡¡es during these reactions¡ A oertain amount of oar¡tion is neeiled in interpreting these results horvever, as the graphs (figures 1d¡) were p.totted' by analysis of the supernatent liquid. from the roaotionso ConsequentlJ/r thj.s tahs no accor¡nt of ad.so¡bed. s¡ncies on the cataþst sutface, and therefore some d.j-ecnepancies may arise. This ï,ould. explain nûry cyclohe4ylidene imJ¡re was nob cletectect by this means, as after d.esorption Ít would. be neactive, cond.ensing with a pri.mary amjJ¡e before gas chromatographíc ana\rsis cor¡Id. be oartied. out. Neverbl¡eless, this method- does show the pth of fo¡mation of the main prod.ucts reasonab\r accurzteþ. , Havirng shoirr that N-cyclobe:rylaniJ.iræ nay be fo¡med' by two patl¡sr ttre question re¡øins as to why it should. be so stable over Raney nickel. Goocl yields of clicyclohe:

(Scrrene lJ).

-fIr -fI o à + + I NiH Ni Ni I

_severÎal -Gteps + N H t/ Ni H

Soheme 1J"

once having fol:necl a d.or¡ble bond. in the al-j.cyclic ring, otremisorytÍon ard. d.et¡yd.rogenation shorrl-d. occìrr much ncre ¡eaùily througþ ttris f-electron s¡æteno If the availabflity of the nitrogen lone-pair is a measure of the ease of chemisorption of these compounds, then the basicíties shoulcl ind.icate nough\r their reactivity towards deþd.rcgena- tiono the d.issociation constant for dieycloherylaurine is ap¡nrently tulcnorrn, but would be expeotecL to be simiJ.ar to N-uetha¡rlcyclohexylanr-ine ruhich has a FKa 11.01*.140 This is a far stronçr base tha¡ {-cyclo" b,e>ryJ,aniline irith a ¡rKa 5.6 ,14 which in turn is stronger than ðipher¡yI- an¡.ine ut¡ich has a pt<ø 0.77.1æ these low basicities coulcl explain wlay md S-cyclohocylaniJ-i¡re is onþ slow\r clel¡ydrcgenated. to d.ipher¡yil,a.¡¡rine, this is equal\r slow\y converteè to ca¡bazo1"J8 (see Table V). Accorrling -78- to this basioity Ì¡y¡rothesis, the fo¡mation of cafiazole should. occur less read.i\y than ciehydnogenation of $-cycloherrylaniline. However, this latter reaction requl¡€s two steps and. the elj¡nination of six tgr¿rogen atcuis, malcing it slow as tho cyoloilelgrclrogenation of, d'iphergrl- aruine which nequirts onþ the removal of two lSrd.nogens" In an attempt to extencl. this series of reactj-ons ¡ the three toluid.ines weIE sin:iIar]y treated. with degassecl Raney nickel, (TaUtes VI, Va[, and VILI). In every oase, the yields of the various d'inetk¡y}' substituted. !-syolohe4ylaruilj¡¡es were lower ttran for I-cyclohexylani.line frør aniJ,ine. The recorrery of unch,anged. toluicl.ine v¡as also greater thart for a¡riLino. The reactj-on of g-to1uid.íne (58) a¡rd. its derivatives ïrcre examined, in some d.etail (f atte VI), and. as ¡-toluid-ine was ass1med- to show sí.milar behaviour, rvas onJ¡r exarnined. brief\r (faUte \rfi). n loIui- d.ine w'ith d.egassed RlneV nickel gave onl¡r 5ft yíeJ.ð' of the mai¡r prod.r:ot, I-(Jqcethflcyoloheqrl)-¡c-toluid'ine ( 29) , añ J'flo recovery of starting material. Apar,ü from the isolation of, smaIl quantities of po\rmethylenet anit that no JrJr-¿¡¡etlr.yld.iphergrlanr:i¡e (¡+) tn"" separnated, the reaction uøs sí.uilar to that of aniLineo It ís assr.uedthat the slight or¡erall d.ecnease j-n activity must be due to incneased, steric j¡eteæction of the rett¡yl group slow$ng the lSrd.rogenation of toluiùine to J-metþylcyclo- (lg) heryIanine " [!Ìre muoh srìa1J.er yields of carbazole d.erirratives may also be explained. by steric hinchanceo fhe metlryl groups of {-(5-raethylcyclo- [sittinglr he4¡l)-g.tofuiaine (29) cou}d. prevent the alioyclic ring from T.ABTE VI

Beaction of

m.tolui- 2¡5-êi-netþI- N-cyclo- I{-(J-r€thyþ !-(J-rcettrY]- Other cline anil-ine hex¡r1- cyclohe:çyl)- cyctohe:ryl)- n-tolui- aniJ.ino n'..toluidine Products clane (ctr.)-, (o.o+ oluidi¡e 5.5 s); n J-nÉtfiylcycJ-o- hexanone, 1o.t+) ; mixbure of c¿¡ba- zores (o"tz g)" (cur)*, (o"o5e); I oluicl.ine + or \c 1à. ,5 rrl:u(ture I @rbazoles" hoqrlamine (")

anilj.ne, (trace) hexylauúne tr:ace 68 " aniline, (lh di- m'.tc]-uicli¡le + cyclohe¡ylamine t t:iace (2.5); N-cYcre- an:Lne (a (¡) 13 herylanilinet (16). aniline, (t.o); + J-¡letla¡r1- 100 trace !-cYclohexYl- (¡) anj-line, (trace) . ") (") Equimolar quantities. (u) Reaction carrieè out in xYlene. -80- f:lat on the catatyst surdace, consi-derabl¡r inte¡fering with the þdrogenation. Yfith very small qnantities of 5 ¡Jr-ðj'mettryldiphergrl- a¡nine fonned., the main ¡'oute to øùazo1e is stiflIed' The ca¡bazol'e mjxture which was j'solatecl was sho¡vn to be cartazole (Zf") and. one other compound' n¡hich was isolated' by pre- pa¡3tion thin-layer ohromatograpkSr, and. could. not be selnratecl into

ar¡y otþer components by gas chromatograpÌ5ro This compound' gave the ootrect analysis and' had' the requireð moleoular weigþt (mass-spectrul) for d.i¡rethylcarbazoleo The n.mor. s¡rctrrum showed trrvo methyl absor¡> tions sepa,rated. by about 2o5 c.P.so Îhe arcgtatic absorption was not anaþzed.o Hence, it may be assu¡ned. that the compoqr¡d' is either 2t!- cLi.netþrlcarbazole (lÐ, or a mjxture of the various possi-ble isomers; 2rl-¿iro"tþloarbazofe (¡6), |r}-diÃtßtÌ¡ylcarba zoLe (35), and l+r5- di.uetÌ¡ylcarbazole (lù. 2r7-Di¡retlsrloartazole is the on1y pzeviously reporteci *rfriof, has a melting point of 281o comtr>ared' to 229' "xampler'9 ?Joo for the isolated sampleo Assrrnuing that the d'irnetlrylcaùazoLe isolated. was folrrcd' from 1r3t -d)rettryldipher¡ylaurine (lù , Gatalin

mod.els suggest that steric clash between tt¡e truo netltryl grouPs r¡r¡ou1d' ¡rr1e out 4r5-di¡reth¡rlcarbazoLe (37)o AIso i,]rte 2rJ-di-urettgrl d'erivative methyl groups Ç6) on forn::ing woul¿. show a sligþt steric clasb of ttre with the oata\fst surÌfaceo As these oatalytíc ¡eactions have been shoYrn to be gensj.tive to sterio faators ,4 Õo it is proposed that tt¡e stnratuæ of this oa¡ibazole cl.erivative is 2r!-cli.uretþIcarbazoLe (35). -81-

G{ GI 3 3

N Gi GTT 1 H 1

(.¡¿*) GE)

N Gi CH 5 CH 3 ctr ti t H 3 (¡u) (16) Gi CH 3 5

\ N N H H

(¡+) ßt)

By analog¡r with the reactions with anil-ine nixecl w'ith cyclo-

he:rylaruine, ;n-toluiil,ine and. J-nettgrlcyclohexylerulræ with $-p Raney nicket gave the pred,icted, nesult, proving a good. s¡rntheti-c patkway to

( t* other !-(l-netlrylcyclotre4yl)-grtofoi¿itte 29) . In this series, ¡rixed. experi-mentõ were cagied out, both applicable to synthetic routes'

J-Methylayclohe4ylanine nas add.ed. to arriline whtle tæated' with d'egassed' oatalyst in :rylene solvent as d.escribed. earlier, and' gave J1/" yielä of, m'tolrrld'ine was refLuxed' I-(l-u¡ethyfcyclohe:çy1,) aniline (+t ) " Si-urilar1y, in :ryIene wÍth lY-ä Raney nickel and cycloheXylanino ad'd'ed', resulting tn2{" yielcl of{-cyc1ohe4yl14-toluiaine (4O) as the main pnoduot' this reaction rvas follonecL by gas clrromatographf as befo¡e (Fi'gt¡rc l¡), shovring (Sctrerne 1f) tbe fo¡mation of eigþt procluots " -82-

H Mz Nti (¡a)

- (26) (æ) 5 (8) (26) (8)

H H N

H Mz }üi 2 rtg. -> tq -> CH cHr *.5 3 3 tnJ ßg) lzt) ( I e) E NHz N

ffi3 *., (+t '(¿¿) ) -€3-

5O

¡|o

û 5o .9o

H .rlo +t d f{ +t k 0) Ê20o n¡-toluid.i-ne n s. cyclohelcylamine

l0 t

aniline

2, thylanil 0 Hours ûO 20 50 40 50 B.eaction of 4-toluid.ine ar¡d' cyclohe:rylamine w'ith W-P EaneY nickelo -8¡{'

50

¿|o

30

20

10

-(r-'" 0 I{ours 0 20 30 ¿+0 50 @ - Reaotion of m-toluidine and oyoS'ohe:rylamine uith TÍ-JJ BaneY nickeL. -95-

lhe formation of 2ri-dimelþlaniline (æ) i" preswrabþ analogous to the formation of o-toluicline from a¡rlJ.ine. J".k"onJL has re¡nrted' the reaction of t-toluiaine (4¡) over W-ru Raney nickel, but on3¡r d.eteoted. the fomatíon of benzene, toluene, pogmetÌ¡y1ene, and. a white solid (0"0, e) witt the samo nelting point as 3 r6-èi-netlryloarbazoLe.

TA3T,E VTI" Reaction of p-toluid.ine anQ zelated- corrpound.s wj.th d.egassed. Rane.v nickel-¡ tÁ Yields.

Compound. 3-toluictine Other Prod.uots

¡-toluidino 6t 10 (c,ur)*, (o.oz e); à-xoethYr- cyclohexanone, (o.05) ; 4 rlrr -di¡nethyld'ipherlylanri.ne, (o.oi);'uazãiás, rixtuæ of can- (o.t4 e)

þtotuiaine + Il-,nethrlcyclc]- 2.5 6+ li,"r.vl".oÈrre (^) Itot

I

(Ð Equi-molar quantities (u) Reaction carriecl out j¡r ¡Yleneo -ô6-

On nepeating this experirnent (taUte VII) r in ad'dition to these compounds, I-(Þmethylcycloheayl)-¡-toluid,ine (¡¿), [,]¡r -ði- retlryld.iphenylanrine, Þmethylcyclohexanone ar¡d. oarÐazole TveIÞ isolated' The ca¡bazoLe.obtained. was mixed. u'ith rvb^at appeaned' to be Jr6-dí- nethyloalbazoLe, but this was not isolated' or positiveþ iclentified'

H NH 2

gli cil CH 1 5 t (+¡) (,l+)

-11{o U-(t-ætlry1cyolohelryI)-¡-¡eLtia:ine (¡4) l¡vas prelÊrcA in yield. by treating ¡-toluid.ino in xylene over d'egassed cataþst with lr''

æ tt¡ylcyc I oh erqrlanine . The neacti.ons of o-toluid.:.¡;r" (lÐ wene fou¡rd. to be anorna*lous 'reactior¡s (tatfe VIfI) o Analege¡r-s to the tolrrid,ine series vlere }j¡ited' by steric factors as the ¡rettgrl grouP ap¡nrentþ interfere¿l' with ohemi- sorptíon of the nitrogen atom as well as the phenyl ring. This is inèicated. by a large proportion of d.e-methylated- productsn g-loluidjne

with d.egassed. Raney nicket gave: aniJ,irre çZ.S%), N-cyclohercylaniline (1g/"), pol¡rnetkgrtene (O.tt9 g), carbazole (0.04/0) , arñ' N-oyclohexyl-g- toluidine (1.6) (¡"yÃ), aJ.1 products of d"emetþlation. However, net¡grlar' tion was also obsen¡ed. i¡e the isolation of zr6-dimetþIaniJj-ne ('t*¡) *ra indole (lz) , anct by the d.etection of J-methyLj¡raore (15) by thi-rr-layer ohromatograPl\ïn ld.entifioation of 2-nethytoyolohexanone once again TÂBI,E VIII

Y Re of th d.

g-tolui- 2r6-di:nethyl- !-cYclo- N-cyclo- Other Produots Conpound. Aniline d.ine he:cy1- hexyl- aníl'ine o-toIui- cline

(o.tt9 g); o.toluid.ine 2.5 65 ¿+" r+ 10 5.5 , , (1 .6); J-urethyl- , (trace); 2- netlgrl cycl ohexano ne, I (0.6 g); caúazoIe, @ (o.oz) I "

o-toluid.ine + 2.5 21 9"5 51 25

+ 12.5 I c I 7.5 3"8 50 (¡ ") )

(") Equ5rnolar qr.nntities. (u) Reaction carrj-ed out in xYlene. -88- supporbs the postulate of a keti.uine inte¡med'iate.

CH Gi cH a t 5 H H 2

z

(+¡) (t6) (t-z)

the reaction of a mixture of etoluid.ine ancì. 2irnetfurlcyclo- he:qylamiræ r¡ras serior:sþ hird.eredo Instead. of obtaining }arge yield.s of !ü-(2-methylcyclohe¡y1)-¡-¡oluidine (JO) as re¡nrted. by Köhncke arul 67 .Hanischr-' this... product corrld. not be isolated. but uray have been forrned' i:: sna.tl yielcLs ( 1SÐ as gas chnoratographic ana.lysis shov¡ed. at least two r¡nid.entified. peakso fne main prod-uots were {-cyclohe:qylanjline and' (47) a1so .U-cxolohe:ryI-g-toluicline (46) . ¡-(3-rnetrrylcycl'ohe:ry1) aniliræ cou1d. not be isolated., but may have been formed' i¡c snra]-l yield's" si_urilarþ, o-toluid.j¡re with cyclohexylarrine gave a large yield of !-cycJ.ohe:qylaruine and a smaller yield' of !-sysLheayl-9- toLuid.i¡e (4.6).

It is assumed. that this d.emethylatíon is the reverse reaction of a-methylation which was observed. with arcmatic a&i¡es. the d"emethyla- tion is favou:¡ed with o-toluid.ine probabþ because the metl¡rl group is :read.iþ accessible to the catalyst on adsorption of the nitr"ogen atæ,, and aLso because it supplies rellef to steric strain in this ad.sorbeil state.. Eor exa.urple, o-toluid.ine rnay be d.emetlqrtated. to aniLine, whj-ch lryd.rogenates to cyclohe:çylanine mone read.ity than o-toluid'i¡te would' -99- give z-mettr¡rlcyclohexylanine. Consequent\r, there would. be a gæater concentration of cyclohe:ç¡rlid.ene j¡ríne than the 2ernot\yl d.erivative resulting in the formation of {-cyclohexyl-o-toluid.ine and. N-cyclo- hexylaniliræ as the najor prcducts" Nevertheless, consid.erable methylation also takes place both on the arqnatic ring to gíve 2r6-ai-nettrylaniline (45) and on the sid.e chain, eventually lead.ing to indole and. J-methylind.oleo 0nce agai¡, the origin of these mettgrl groups is abscune, but as the yield.s of these rctlgrlated. prcd.ucts are greater than that obsen¡ed with aniline, then tàe sou:¡ce of some of these n'ay have nesulted. from d.enæti¡rlation of o- toluid.i¡¡e.

o-NaphtþIarrine would. be axpected. to show sjniJ-ar sterio faotors effecting the nitrogen atcrn as a-toluid.j¡re. 0n treating øF naphthylan:tne with d.egassed Raaey nickel r¡nder sj¡tilar cond.itions, no second.ary ami¡es were isolated., a¡rd. the onþ detectable :¡eaction was a

1ú1, deurÈnationo This lend.s supporb to the postulation of steric hindrance in the g-toluld.ine æactionso To gain a greater insight into the neactions of d.i-fferent nitrogen fi¡¡ctions over Rartey niokel, (49) J-aminopyrid.ine "na J-arrirro- piperid.íne (51) were treated. with d.egassed. catal¡rstso The first of these has been :reporbed, by ïÍhitt1"14J *to obtajneil small quantities of a yellow solid rvhich anal.yzed. for d.iaminobipyridylo However, no stn'ctu:re lyas prcposed,.

If J-ar¡:jJroByrièine behaved. in the sarxie way as other J-substituted. ?90- pyriûines wer Raney nickelrl& the expected. prod.uct would. be i rJt - diaruino-2r2r-bipyriqyl (49)" Howevero if chemisorption occurred' thnouglt one amine nitrogen and. one ring nitrogen, or through both ami¡re ¡titro- gens, the fo¡mation of d.ianinopyridù¡e. (Uy . mecha¡risrn sj¡njJar to that pr.oposed, for the fo¡mation of 2r2t-d.ianrinobiptr.nytJS) worrld' result in tlre formation of J rJr -èianino- 2 rlt'bi:rpyridyl (¡O) .

HeN 2

(+a¡ (+s)

H N$ IüI 2 2 N NHH

o a q N HN (¡o)

0n repeating this experÍment, a si-rnilar compor.md (witft tfte

same melting point) oa" obtained., which gave a d.istinctive red coLoura- tion with ferypus sulphateo This test is characteristic of 2r2t- bipyridyl nuoleu,s, md nrles out the other possible bipyrid'y1 isomers. The n.m.ro speotn:m shows an g-proton ( f 2.0À) r¡vith at least one -)1- orbho coup¡rrg of 6 c.p.s. lvhich favours structu:re (¡O). Also the N-Il absorption in the nom.r. spectrum is low ( f l.Al) compared' with for exampler 2-arn-inopyriiLine ( f 5.25)"145 thi-s could be d'ue to d'e- shielcling by the ad.jacent aromatic ringr or by tSrd'rcgen bond'i-ng of the arnine protons with the hetenocyclic nitiogen atøns, both of which couliL (50) on\r occur with S rJr *d.ianino-2 r2r-bipyridtl . J-aur:inopiperidine , (51) on treatment with degassed. Raney nickel, gave )+Ø" yield of Zr2t-bipiperiayf (¡Z)o The forn'ation of this pnod.uct vlas quite unique and. has no i-uned.iate ar¡alogieso Piperid-ine úas been shovm to ,'d.ergo ring contractionrlL6 ¡-"r*L^tíonrlú'147 d.ekgrd.noge*tiorrrl47 a¡¡d. N-s'bstj.tution with a1coholu r50 under the i¡fluence of Raney nickel and. sjmilar oataþstso Reaction conditions these with J-a.minopiperid.ine rfÞy have been too vigorous to observe products, as on$ intlactable tars were obtaj¡red' other tha¡ 2r2r- bípiperi{yt (52). Ihe fornration of 2r2r-bipiperídy1 nay be eicplained. by postu- lating initial ad-sorption througþ the prirnary amjrre group lead-ing to d.ean¡.ination Assuuring that this is followe¿ Uy efi¡n:nation of \rdrogen to give tetralryd.nopyrid.ine (SÐ, this corrld isomerize artð. fotm 2r2r- bipiporÍdyl by a mechan:ism very si-milar to that proposed for the formation oî 2r2t-biPyri(yf% (S"f,"me 1!).

arn analogor.s compound to J-aminopiperidine is 1r2-èlanÉno- cyòtrohexane (54). In both cases, the two nitrogen atoms are separatecl -)2- Ni (: o

$t) I

H + N \ Ni

by two ali¡ihatio carÐon atoms, arrd henoe a sjm:il-ar..reaction shor¡Ld' be j¡nine expeotedo In thie oas6, clearrination wou1d. leacL to cyolohe:çyl1d'ene (2ù (Sctreme 16).

NH NI{ 2 2 2 -MJ }üf 2 H (¡+) ll H, NEi N, sever.'aI <---stePs

(zt)

Scheme 16o -93-

on investigation of the reaction of 1 r2-d-iamjnocyclohexane product with d.egassed. Raney nickelr'N-cyclohexylaniline rvas the main isolated. ín 3Vp yield'. Other pnod'ucts forrned' wer€ g-pher¡rlened'iamine (Sl) and' phenazine $g), trans-1 ,2r3r\rtþrJrlorl}a-octaÌ¡rdrophenazS-ne , (¡A). Octa¡4ydrophenazine rvas probabþ formed. by attack of g-pherSrlene- d.iamine on the dj.jmine (y6) , perhaps jn several steps, then folloted' by witå þdnogenation" The formation'of the ilSl!-isomer is consistent the fi¡¡d.ings of crene and. McrlwairrlÉ .r¡r¡iro shovved' that basic cord-itions for the t¡yd.rogeration led to the iÆ-isomero Phenazine could' fom by L&'1 56 d.elryd.ro ger¡at ion of octalSrdrophenaz inel ( scn"me I 7)'

Nä N 2 +i TñT- 2 N 2 (¡+) $6) I

H }üi N 2

N Nä 2 iT $t) (¡e) $7)

Scherne 'l7"

o-pher¡rlened.iarni¡re (55) was treated. with cyclohex,ylamine and'

Raney nickel in an attempt to pnepare ltt -d.icyclohexyl-9-phenylene- to d.ia¡¡rj¡¡e (¡g). llovrever, in ttris case thene r/rere lrc¡ procluots related' -9ìF o..;*rerSrlened_iamj¡re. aniline Ø6rù, g-toluid.ine (t {") , aicyolohe4yl- a¡ni¡re (U{"), N-cyclohe:çylanilitu (t*7/ù, d.iphergrlanrine (1.Ø"), carbazole

(O.S/") and. stârting nateriat (l*/ù were the on\y pnod'ucts isolated' from the reactiono

NiT

Ntf 2

(¡s) (60)

Once again it appears that the crovrding of' the ortho' substituents is too great to pernrit reactions on Raney nickelo After þd.rogenation ôf o-phe4ylened.ia¡oine to èia¡ninocyclohexane, d'eamination may oocur as i¡ Scheme 16o However, if $-cyclohexyl-o-pherSrlene- a:-anLine (60) di.d. forrn, i,t is possible that the large bulk of the cyclohoryl g:rotrp would. facilitate eliminatj-on of the free aûdrle fi'¡nc- tion (tkrus easing steric str.ain) by d.eamination as d.escril¡ed. earlier. j-n Igr-dicyclohe:ry1-o-pher¡ylened.iani¡re (5g) f¡as rrever been necorrled. the literature. -95-

H ry

H

( 61) (62)

S$imilar pre¡arations r¡vere ca¡ried' out with .g' and LrF pherSrlened.iami¡res with cyolohe4ylarnÍ,neo In each oase, yield's of

25ø NA,-ilioyclohercyl-grphenylene*iaraine (61) and' J(' of Nrryr'- ti;loyolohçrry1-¡rpher5rlenod'5-amine ( 6e) were oþtainecl. -)6-

ÐGERI¡/EJÎAIJ

1- Generalo

, Gas chroÍ¡atographic analyses were carried. out with a Perkin-El¡rer mod.el 800 Gas Chroratograph equippecl w:ith either a 6ft' x 0.125 ino colus¡n packed. wittr Gas $ntpm'2} (8O-t0C mesh coate¿L wityr 15% Silicono grease) or a Jft' x 0o1 25 í¡.. column of Chromosorb-TÙ (AO-1OO mesh coated. with 15"1! APíezon L grease) o Prelnrative gas chronatog::aplr:io separatior¡s wene camied. out r¡'¡!th an aenogra$r autoprep Mod.el A^7OO fitted' with a 5ft" x 0.375 i¡¡o coh¡rnn packeil' with Chrcmosorò-W (6O-80 mesh gas coated. wífh 3Ú/" SE-]O silicone gre"se)o Compound's identified' by chrcnatography were charaotêrized. by retention ti¡res with authentic samples as internal stand.arrls on both the sj'licons and' Apiezon colum¡r"s' Nuclear magnetic resonance (nomoro) spectr:a rrerra dete:r¡ri-ned' with either a Variar¡ DP.6O spectrometer calibrated' relative to tetra- metl¡ylsilane using sid.e4and teohnique, or wj-th a mod:ified-Varian D4.60- I[, spectrør¡eter with fie1d. frequency lock calibration" Chemical shifts are given as f values; solvents were cazbon tetraahlorid'e, deuterated (hO: 60) clrlorof orm or aceton e/ æ;tbon tetrachloride "

tr4ass speotra were measured. with a HitacLri Perki.¡e-E1mer RMU-6D single focusing mass spect:¡oneter using a 7N Íonization potential' Infrared. s¡nctra were measured. witlr a Perki¡pELmer Infracorrd'

337 or 2Jf spectrophotometer. Uttraviolet spectra were d'eterfüned' lrith a Ferkln-Elner 1JJ $Jno spectrophotometero Separations involving column chromatograPr¡y were carriecL out -97- on Mallinctcrodt silicic aoj.d. or Spence alurrina with an ad'soröent- j¡lg ad.sorbate ¡atio of 5O:1 r-l"s hexane , benzene ard' ether as eluants. Thin-layer chromatograpk\y was car"r.ied. out on silicic acid plates

cm preparative plates (Ooe¿+ thick) (0.0, thiok) or .cm " Analyses were perfo¡med. by the Ar.l,stralia¡¡ Microana\rtical Senrice, Melbourne

2o Materi-als.

lhe fo1lq1Íj¡1g compound.s were comner"cial sarrples purified. by di.stillation: aniline, brpo 8Z-83o/15 nv¡; cyclohexylami¡re , b.po 133- 1jt+o; o-to1uid,ine, bop. yrgSo/$ urn¡ ætoluid.ine, b.po 93-940/15 ÍwL. The following were commercial sanrples wieich were r¡sed. w:ithout purifica- tion: 2r6-d.i-net¡grtaniline (Fluka, purunr), ¡-toh.r:id.ine (B.D.H.) I I pJaer¡ylene ðianj¡re (B.D,H"), g-pheqylene d.ia¡¡ine (B.D"H.) r Fphertyleræ d.ianine (A.O.U"), and d.iphenylamine (ntui

t5lr.5o)r J-netryIcyclohe:cylan¡.ine, b,po 61ofiO tn (tit.1''9 152.7-153"4o), arrl ,l¡-methylcycloheryIa¡nine¡ bopo 65oh| o* (tit.149 b"p' 153"3-153.7\ wer€ pnepared. from the co:respond.ing toluid.ine aoetate by higþ pressu-re hyd:ogenation over rrV-/ Raney nickel, and subsequent tSrd'rolysis in 7g/" sulphurio acid' of the nethylq¡cloherç¡rlanine acetate' b'p' lß3-laso/ 1.2-Dia¡nj¡¡ooyorohexane, bep. Boo/15 o* (tit.15o

7zo nn) arrd, J-arninopipericlino ¡ b.po Azo/t5 o* (tit.151 b.p. 7-7f /1o vß) -18- were siJnilarly prepared. from g-phenylened.iàmine anr"L l-aninopynid'jrle r€speotively. 2¡5-ÐirnethylaniJine, bopo fizo/15 mn (tit.153 b.p. z15o) nras prepare¿ fron ¡-:o.lene by the method of Nl5lting and. Fo""I.l53 X,y1ene solventr boP. 137-il+Oo, and benzene were freed' from

sulphur conpor.md.s and. purified. by d.istillation from Raney nickel"

1¡-7 ard. d.egassed, Raney nj.ckel uere Prepa:¡ed as d.esoribed- in

Ghapter I"

5o General Reaction Conditions. (i) lilith W-7 Rane,y nicke\ - The oata'Ìyst (fnom 125 g of 1:1 (Uy n:lcl

d,escribed. in Chapter I, a¡ô. the nrj¡rtu:re refluxed. for þ0 hor:rs' In some experirnents, aIL ga.ses issrring from the cond-enser were Passed' throqgh 1N lgrd.rcohloric acid. solution (5OO nf) to d.issolve ar\y basic volatile material given off. Ihe yield of these compound's (assr:med' to be nostl¡r

auuronia) was d.eteznrj.ieed. by back-titration of this solution vfith 1N period', soclium kgrdr.oxide solutiono After completion of t'k¡e ræflucing the solution rras filtered. througþ a glass sinter (porosity 4), and' the (Z5O catalyst washed. wiür hot methanol (Z¡O mf) and Ìrot benzene *f)' and' Eiltr:ate ar¡d. washirÀgs were combined, the solvents reuioved', the liquid approxi- ¡residue d.istilled. througþ a claísen d.j-stil*Lation apparatus at out by nate\r 15 m pt¡essureo Ana\rsis of the d'istillates were carz.ied' -99- gas chromatograplry. The residues from the ôistillations were furLher irvestigated. by columr¡ chromatograPl:J/.

(ii) With desassed. Rane-v niclcelo - After cooling the oatalyst (fronl 125 g of alIoy) ard, closing the appaletuse connectior¡s to the water pumps, the amines r/rer¡e ad.d.ed. (thoroug¡1y wettj¡g the nickel) before ad,rritting air to the apparatuso The ¡nixtu¡re Ïras then refluxed' (cao for 50 hourso In some exper5ments, sma1l samples 1 +) wene taken from ttre reaotion mìxtuæ at h¿r¡o hor:rþ interwals for the first 12 hours, ard. tlren at 24t 26, ar1d,48 hours. Ihese samples we:¡e investigated' by gas ctrnomatograpþ using suitable stand.ard nixtures for caLibration.

The reaotions we¡¡e analyz€d for pæducts as d.escribed. jrt .5(i).

(iii) lflith d.egassed. Ra¡rey nicket in x.vlene" - The catalyst (fron

62., g of agoy) rrras cooLed., an¿ sulp¡une-free xylene (50 r¡¡) add.ed' covereè while the nrater PìlmP oq!.lllections were closeðo The catalyst uras with solvent ar¡ô the appa¡atus opened. to the at¡oosphereo The aromatic arnjiJ¡e was add.ed, to the urixtut¡o, and. reflr¡ced. rvi'riLe the a1i$tatic amine r,fas ad.d,ed. dropwise over a period. of 1.5 hourg. the rnixture was then

:¡eflr¡ced. for 30 hourso X'iltration and. d.istillation of the prod.ucts was oa¡ried. out as describecl i¡¡ l(i)" -1O0- l'- Specific Reactions. (i) anit"ineo (") t¡Jith W-7 Raney nickelo - Anilirre (gl e) was treated. w.itt¡ T,I-7 Raney nickel as d.escribod, Ðisti]] ation of the reaction pnoducts gave aniline, bopoEOa5o¡21 rrn (4, g) arrd N-cyclohexylaniJ-i;ne, bop. 155-160o/21 rm (1, g) showing trnaces of d.icyclohexyla.urine, leawing ' a d.ark brovm oiþ nesidue (6 g) ïfh:ich uras not further i-nvestigateôo Back titration of the kgrd.rochloric acid. solution in

mm (9.5 g) 1¿po/15 nun (8,6 B) rad (c) ¡-cycloue4yranjJ-ine, bop. \5o/Þ . Fraction (U) was a m:ixture of aniline (65/") g-to1uid.:-ra (lq/ù, and t¡aces of !-cycrohexylaniJineo The d'arl< solid :¡esidue (5'g g) from th:is ùld- tillation was separated. into basio (r.1 g) and, neutral (2"7 e) fractíons witl:- 5r/. aqueous lgrd.roch1oña acíð/ethero [he basic residue oontaj¡red. (1 g), tarry int¡ractable rnaterialo The neutr¿I {..cyclohe4ylaniline "d fraotion rras ck¡nomatogra$red, on alumina to give ùiphenylamine (t.26 g) , mopo and. Eixed. rrrop. r 54o arrd carlcazole (O"57 g) , mop. and. nrixed' IIloPo r a 2l+Do o The catalyst after filtration yras extracted. e:ckraustive\r in Soxb-Iet apparatus with benzene, which on øva1nr^ation Lefb a brov¿n :residue (0.25 g). No pure components wene isolated. after chromatograpl¡y on alu¡nina, but thin-Iayer chroriatograpl¡y showed. conpounds ïÍith Rf values \ -101- 1 cornespond.5.ng to dipherrylanine, indoler a¡d. carbazole. The Presence of indole was also ind.icated. by a d.eep red. color¡¡ation with ¡-d-ímethyl- 6 a¡ninob e n zald,etq¡rd,e o

(ii) lX9I9IlexvIgSiE. (") vùith Tì¡-7 Râney nickel. - cycJ-ohe:çy1a¡n-ine (gg g) '',tt"" j.on refh¡xed. over T'I-7 Raney nickel for 50 hours. The solut was filtered. as before, and. on d,istillation gave (a) an oil- b.p. !O-1 2Oo/21 ren (7 d t (b) b.p. 156-158o/21 û!û ßE e)o Fraction (a) "rrd !-cyclohe:çrlaniline, was slÀsvrn by gas ctrronatogrraphy to be aniline (64ò a-nd. ùlcyclohe:çyl- aÍuirreo fhe ligþt brown reoj.d.ue (Z ù from this &istillation was not irivestigated. furbher. litration of. the lgrd.rcchloric acid. solutíon jnd.icatecL O.5S moles of ammonia was given off"

(U) ï¡ith d.egassed. Raney nickel. - Cyclohe4yla¡nine (gg S) t*"" ref\¡xed. with d.egassed Raney nickel for !O hours as d.esoribed'o EiJ-tra- tion ar¡d. òistilLation of the crud.e reaction ¡njxture gave (a) a oolourless oiJ, b.p. 11o-15oo/19 m (12"5 g), (b) !-cyclohe:qylaniriner b.Po 1550/19 nw

(¡O g) ar¡d. a b:¡or¡n¡ so$.d residue (¡.9 g). Eraotion (a) oontained' aniline (ZVù, èlcyc1ohelylanri-ne (íò , and. !-cyclohe4ylaniline, a1I id'entified' by gas chromatograp}gr. The a¡nmonia collected. was equivalent to 0.56 mo1es. The residue from the èj.stiJ.lation v¡as separatect into basic (t.O g) and. neutraL (2"5 g) fractions. The neut¡'al residue was chronatograpkreô on såJ-icic acid. ard. gave d.ipher¡rlan¡:ine (0.+ g) I B.P. and. nrixed. m"P. 54o -102-

o a¡rd. ca¡bazoLe (1.2 g) r &.Po and. niixed. m.P. ?h3-W a The basic resid.ue ccntained' on\r S-cyclohe>qyJ'aniline ar¡d' tars'

(iii) Anilinç and.-lQvqlohexvlamine. (") ]ll¡ith I,u-7 Raney nickel. - A nixtr.rre of aniline (56 g, (59.5 g, o.5 moles) was ref¡:xed over 0.5 uoles) "td cyclohe:çy1a¡nine W-l Raney nj.ckel for 5O hours. Filt::ation and. d'j-stiJ-lation of the resnlting ¡uixture gave (a) an oi1 boPo r 9È1Þ0/19 m (8 g) which was showrr by ga? cLrrornatography to be aniline @2. 95%) with traces of o- toluid.ine and ci,icyclohe$rlanine, and (U) ¡f-cyclohe>çylaniJ'ine, b.p. ¡ 155-16Oo¡tg no¡ (¿+1 g). The d.arlc broriyn solid. residue (6 g) was not fr¡rthe r i-nve st igated.

(U) ïtith d.egassed. Raney nickel-o - Cyelohe4ylaraj¡¡e çttZ.l e,

O.1?S noles) was ad.d.ed, dropwise over a period. of 1.5 bours to a re- flnxing solution of aniline (tZ.O g, 0.125 moles) i.n sulphure-fuee rylene over d.egassed Raney nickel (prepar"ed. from 62.5 g of alloy). The solution was naflIuxed. for J0 hours and. prod'ucts ¡¡ecove:red' as before' DistilLation gave (a) an oi.l bop.80-t00o/15 nn (0.5 e) rvhich uras shown by gas chnouratograpL{y to be a núxtr:re of :çylene, aniline arr1 d.icyclo- he:çylarrine, and. (u) g-cyclohe:çylanili.ne, b"p. looo/1.2 wn ('t5"5 g).

The resid.ue (0., g) was ct¡:¡omatographed. on aLr.¡sÉna, but no pure prod'ucts we¡e i.solateô"

(i") tt-cvcfohexvlanilin" wit . - {-cyclo-

d.egassed' Raney nickel for 50 hours he4ylalril:,ne (1OO g) ',ras reflr¡xed. with -103-

and. the products recove¡ed. as d.escribed. Distillation gave (") -N- cyclohe4ylailili4e b.p. 1l¡O-ß00/16 ¡nn (70./ g) which was shown by gas chroroatograpl\y to be contamj¡rated by traces ( 1E% by anea) of and. (¡) aniline, ðicyolohe:çylamÍ:re and. five other minor components, " light yellow solid. residue (l.S g) vrhich,¿vas separated. into basic (t.O e)

arrd. neutral (Z.Z g) fractj.ons. Chronatograpk¡y of the neutral nasid.ue on a}q¡:ina gave ðlpleenylarr.ine (t.O dr iloPo and. mixed. IIIoPor 5J+o a¡rd. can' bazole (1.1 g), mop. a'¿ mixed. nopo 2,1+l+o. The basio t"".¿ie' was star'üing naterial"

(") ø-Na¡hthylar¡:ine with degaq . - ø-Naphtl¡y1's,ine

(71.5 g) .ri,¡as add.ed. to the oateilyst '(prepared' ttom 62.5 g of afloy) with

sr:lphr,m-f ree ]oenzen" (25 mls)" lhe benzene was d.istiJ.led. f¡pm the lleâc- tion ni¡

anine (5O.2 g), b.p. 116-1180Æ.8 nrn. The black solid. resid.ue (7.O e)

was chrcmatographeå on alumir¡a, but gave on\r fr¡rbher starti'8 rnaterial (+ d and. highly ooloured. poI¡rmerie materiaJ.o

(ni) :o-Ioluidine wit-h desasse . - g-Toluid.:¡¡e (t5O g) was tæated. with catalyst as prewiousþ d.escribeê. Distillation of the cn¡de reactÍon mixti¡r¡e gave (a) o-toluid.fne (56.5 g), b.p. 95-102o/25 nn (g%) which was shown by gas chrornatograpt¡y to contain arriline "t¡ traces -10.lr- of 2r6''JimelhylaniJ-i-ne, ana (u) *, oi1, b.po 1O2-166o/2J m, (Zl e) shown by gas ctrnonatography to be a mixture of o-tolr¡idi:rre (89/"), 216' d.funetlSrlaniline (lS"/ù and N-cyclohe:ry1arrl1ine, and. (c) an oil bop. 166-1700/25 ro¡ (eO e) shown to be a mixtur.e of .$-cyclohexylanilíne (6Vù , N-cyclohe:qyt-o-toluid.ine (l¡û and. tiraces of '-two other compor:nd's w'ith longer retention ti¡eso lhe black tarr¡f' residue ('8.5 d *." d,ivided. into basic (5.9 g) and neutral (7"t e) fr^actions 'vrltb' 5% Ì¡rclrochloric acid. solutíoty'ether. Chromatography of the neutral residue on siLicic acid. gave, on elution with hexane, (.) pol¡rrTethylene, m.p. l+7-49o.(0.119 g),

(¡) bro',yn solid., m.p. (o.93 g) shown by thi:r-Iayer chrromatograpþ " 35-t+Oo and. colouration with ¡-d.imethylalri-nobenzal-defry¿u6 to be a nrixtr:re of indole and. J-nethylindole, (") i-nd.o]-e, ñopo ârid. njxed' m.p. JzoC (t.88 g). gave (a) white so1id., rlropo.lgO-2OOo (O.tO g) and. Elution wi-th benzene " (") d.ark red. oif (l.OB g) the ir¡frared. speotn:m showing a cartorgrl " , strratahing f,requency of 1715 cm-ío lhe ojl (e) was characterized' as 2- mettgrlcyclohexa¡lone by its 2rÞd,j^nitrophenylkSrdws¡1e d.erivativêr III.P. and, mjxed. m.p. 1560o The white solid. (¿) na¿ årI rrolllox¡ spectrum very sj¡riIar to æùazo}e with a small singLet ( < t proton) at 7.1+5. Gas ch:romatography ind.icated. a mixture consisti¡¡g rost\r of e:;frazole (ca. 86{.) ana at least one ottrer component. n'ractional recrystallization faiJ'ed. to yie1d. ar\y pure compound.so

(uü) o-Îo+idine and 2-meth$ry 4ig!4, - A nrixturre of 2-melhylcyclohexylanine (æ e) ar¡d g-totuid.ine (j7¿5 d was ref¡xed. for 50 hours over the cata\rst, -105-

Filtration a¡¡d distillation as before gave (a) an oiJ. b.P. 105-lt5o/ (c) a 15 (ro d , (u) an oi-l b.p. 60-1 oo:o/z.o Ím (15 g) , ana vello'nr .uñL oi1 bopo 110-1 ZO}/2"O n* (r5 g). Gas chropatographic analysis of these (ltt/ù arÈ- 216- fractions shor¡ued. (a) r,'as e-toluidine .(eÚ/"), anj-1iræ d.i-met\ytanjJ-ineo Ðraction (U) vras g-to1uid.rn" (5Vt anò- 2,6-a:rnettryt- a¡riline (+t%) with tr':aces of two other components, vlirile (c) vlas !- cyclohe:çylan1Line (OS/ù and. !-cyclohøçyl-a-toluid'ine (Wù with small quantities two other components with longer netention tj-mes. @ S%) "t

(vl+i) o-To]-uidine and cyclohexyl ' - o-Toluid.ine (55 g, O"5 mole) and. cyclohe4ylamine (trg.5 g, O.5 mole) we:re refh¡ced. oyer the oatalyst for 50 hpurs" The c¡ud'e prod'ucts were fil- (b) tered. ar¡d. d.istllled. to give (a) an ojl b.p. 8O-1OOo/15 h (¡ g) , an oil bopo 100-ßOo/15 nm (ZO g) and. (c) an oil b"po 100-12Oo/2"O Íß (L¡ d o lhe oil (a) was shov¡n by gas chroratography to be o-to1uiðine (8g/") and. arrit ineo Eraotion (U) was a m'ixture of o-to3-uid.jne (ZV/ù , (El/ù traces of Z ri-ðinetnylanlline çZS"/ù, !-cyclohe4ylanitíne with d.icyclohe:

(¡,) - ;r¡'Toluiòine (tlo e)

rryas refluxed. with d,egassed Rarrey nickel for 50 hou¡'s as previou'sþ -'106- d.escribed., and. the reaction products filtened. Distillation gave (a) g-toluid.irre bopo g&llX}o/z0 nuT (80 e), (U) an oil b'p. ¡ 1OO-1t+5o/15 rrrr-

(lZ g) sho'w¡ by gas chron^atography to consist of 4-to1i.¡-id.ine (l5fr) , 2 þ-dLmethylanilíne (+ZÐ and. N-(J-¡¡stkylcyclohexyl) 1g-toluld ine, and' (l the (c) I-(j-*"tkgrlcycloheayl)-g-to1uid.i¡re t.p., 12oo/o.g mn e) " thick black tarzxr residue (7.t e) was

shorved this to be a ¡rixture of carDazo]:e ard. at least o¡:e other component.

(*) m*T olui.dine and. v'l r:vc wl-th tleøassed Ranev nlckel* - A nrixtu¡e of J-methylcyclohe:çylamine (ZS g) and.4- tolui&ine (zz ù was added. to degassed. Raney nickel (rrom 62"5 g of alloy), and. ref!¡ced. for 50 hours. Fil-t¡ation ard. &istjJ.lation as before gave (r) * oil b"p. , 11p1t+5o¡t6 o* (Z.O e) ar¡a (¡) N-(5-¡cethylcycloherçy1)- ¡¡.toluidine b"p. 115-12Oo/Q"8 ñrt (ZZ g). The fraction (a) was shorvn by gas chnomatogra$ry to consist of rrrtoluid.j¡re (Bftù e Zr5-dimetk4ylaniline

ar¡d traces of two other components. Fraction (t) was purj'fied' by d'is- tilLation througþ a¡¡ I ino Vigreux column to give pure }-(J-ræthylcyclo- hexyl):E-toluid.j¡re b.p. lJO-131o/2.2 ñrL" (nouna: C, 82.6; H, 1C"J; Nr

6o9. CthHZ.¡N neguires: C, }Z"ii H, 10.4; N2 6"fl"). The rl¡Ilrrro spectn'un _107-

(ccÐ shoued. aliphatio mettryl absorption at 9"08 (aouutet, J * 6 c/s) a¡¡d. an aromatic methyl at J.JB (singlet)' [he tÍght brrcyrn solid. residue was chncrratograitred. on alr:rnina to give (a) a ye3Jow ojf (1.18 g) an¿ (¡),a white soli¿ (0.28 g), mop.

220-25Ooo The yetlorv oil (a) was separatèd. into basic (0"58 g) and.

¡æutra.l- (0.51* g) fractionso The neutral fbaotion was rechromatogra¡ùred. on silicic acid. to yiold. poJ.¡nnethylcno rrropo )+9-5Oo (0.05 e) and. a clear oit (O.h g) wlxi.f, cor¡J.d. not be crystallized., and having an ultravíolet absorption si¡;ilar to èiphe4ylamineo Ïhe white so1j-d' (U) was shourn by gas chromatograptgr to be a rn'ixture of a carbazoLe (Zf/,) and. at least ore other componento The second component Ìras separated. from carbazole by preparative thin-layer chromatograplry arrd. crystallized. from hexane as colourless plates of dimethylcaröazole¡ n.P. 228-2290 (For:nd': C, 85.1¡; 8., 6o5i N¡ 7o2o cl¿IIt¡N requi-r'es: c,, 86.1i H, 6.7i Nr 7."/")o lhe mass

spectrurr had. a molecular ion and. base peak at uy'e 1)J, 'whích lost two successive mettryl groups (56% ana 1(" of base peatc)o The rIoIrI¡To spectn:n

(coC1r) showèd. aro¡natic rethyl absorption at J.iJ anð' 7.57 (6 protons) an¿ in acetone/ca¡bon tetrachlorid.e showed. ancmatic proton absorption fr.our 1 o95-3"13 (ã prntons).

("i) j-Methylcyclohex.ylarn-ine_lmliqþ deg-assqd Rane.y nicice}., - J-Metkgrl- (ZS cyclohexyla¡rine (ZZ ù was reffi¡,xed in methylcyclohexane "l) over d.egassed. Raney nickel (frorn 62"5 g of al-loy) for 50 houzs and. th¿e cataþst

then reooved as beforeo Distillation gave (a) an ojJ. b.p. 1/O-ßOo/1¿+ ßm

(e.f+ S) .nd (b) $-(J-uretkrylcyclohe:ry1)-r5'trq1tid'ine, b.p. 19Ú195o/1h nm -1 08-

(12.5 e). fhe ojJ, (a) was shovrn by gas c]rromatography to be I-(¡- nethylcyclohe:qyl) -¡¡.t o1uid.ine @,. Sgiù, t rac e s of -nr.toluid.ine anrJ. aniU.r¡e, and a compound @," SV.) with a retention time very sjmilar to d.icyclohexylanine. The d.ark resi¿ue (0.À- g) cornd, not be separated' into ar¡r pure components.

(r¿l) - A ni¡ctune- of ¡r*toluid"ine (fi g, 0.5 rnoles) .td cyclobexyla¡iine (+g.5 gr 0.5 noles) was reflr¡xed. over the catalyst as before. Small sarrples @. t^f) were taken at vanlous intervals d.uring the reactJ-on, and. were i¡westi- gated. by gas chnornatography. Products were fj.Itered. and d.istiIled. as pr"eviously d.escribed which g.ve (a),an ojJ. b.p" 9O-ltoo/þ nm (14 dt

(U) 8O-1 OOo/1.8 nuo (15 g) (c) a yellow oil bop. tCo-tZOo/ an oi1 b.p" "r,a 1oB m.r (æ g). Gas chrormtograpl¡r sbowed. that f¡action (a) was anilir¡e ard m-toluid.ine (ZlÐ and. fract:-on (b) was rrrtoluidine (+SÐ, 2r5' d.i.rretlgrlaniJ-ine (tg") and òicyclohe¡ylanr.ine (lSlL) with traces of aniline.

Fraction ( c ) contained. N-cyclohexytaniJ"Íne (lZfi an¿ N-cyclohe:qy]-g- toluldine (65%) Jrith t¡a.ces of N-(J-¡aethylcyclohe>çy1)arriline ana A-(5- nettrylcyclohe4yl)-rn-tolu:ldine. Distillation of (c) througþ an I in.

Vigneuc colunr¡ separated. pune S-cyclohexyl-m-toluid.j¡ee a.s a colourless ojJ- b.p. rclo/o.t r* (1it.157 b.p. zooo/3o ßrl.) (nouna: t, 82"5i H, 9.8; Nr 8.2o Calco for C.,rH.,rN: C, 82.5; H, 1Oo1; N, 7.ry")o The nelnrrc

spect::nm shorryed. an arcrnatio methyl absorytion at J.82 (singl.et). -1 09-

Ixr.a]./ ål_IXkIgg - Ir.njJ,ine (tZ.O g, O.1J moJ-e) ¿ìissolved. in srrl"phu:r- free 4ylene (40 mI) was refJr.¡xed. over degassed Raney nickel (fron 62.5 g of alloy) and. J-rnethylcycJ,ohexylamine (15 g, O"1J mole) acld.ed. slorvþ as previousþ d.escribed.o The nrixture was :refluxed. for !O hours and. the catalyst then ¡¡emoved. by filtration. DistjJ.lation of the cnrd.e ¡eaction

¡rixture gave (a) an oil b"p" 5O-'iOOo/1.5 mm (1.'t g) shorvn by gas chror¡ta- tograpkry to be N-(J-metJeylcyclohe4yt)aniline (56/"), aniJine (Z5lù and. g- tolrrid.ine, ad (¡) $(¡-metl¡rlcyclohexyl)aniline r b.Po 119-121o/1o5 Irú

(19.5 e) w:it¡, traces of S-cyclohe:çylaniJ-j-:ee and. A-(¡-"tti,ylcyclohexyf) -o* toli¡-id.itre. N-(J-netkrylcycloheayl)anil"ine was purifi.ed. by d.istillation of fraction (b) througþ an I ino Vigrerx ooh¡sur to give a colourless oi3-, b.po 119o/1.5 rwn (¡'oun¿: cr 82.Q; tl'r 9"7i N¡ 8.0o cljH.gN requires: C, 82.5; H, 10.1 ; N, 7"4/ùo lhe nernoro spectrr:ur showed a methyl absor¡r c/s) tion at 9.09 (aor¡let, J o 5.5 "

(xiv) - B-Ioluid'ine (tZo e) vìras ïranned and. ad.d.eê as a J"iquld to the eatalysto The mixturê vra$ i¡ê- f}¡ced. for !O hours ánd. fiJ-tered as before, and on ùlstilling gave (a) p-to1u:i-d.ine, bop. 100-1400/26 wrt (1Otr g) contarainated. with t¡aces of two other components, (b) a 1igþt yel]-ow oiJ. b"p. 140-1 90o/26 o* (¡ð d con- tai.ning I-(4-߀thylcyclohexyt)-¡-toluldine @" 5CÍ,) and three other compoundso rhe d'ark red' liquid. residue (tl.z g)'rv^s d'ivid'ed' into basio (6"f S) and. neut¡at (3.4 g) fractions. Chrrcmatographf of the neutiraL -llC-

(b) residue on alum:ir¡ê gave (a) pol¡noethylene mopo , )+7'l+9o (O.OZ g) t

þurethylcyclohexanone (O.OA g) characterized. by its 2r'l+-di:ritropþergrl- (O.OL g) l[¡drazone mcp. a*¿ mixed m.p. 1340, (r) Lr4t-d.i¡nethyld'iphenylannine (a) crystal1lzed. from aqueous ethanolu rrropo 78-79o 1fit"154 7go), ana a white solid. (O.f+ g) m.p. 2OO-2O5o'. Gas chromatographic a'alysis of the so1id. (d.) sho.red. it to be cartaz o]:e (z5o/.) arrd at least one other o

(*.') and. a nic4ef in xylene.. - l¡-Metlvlcyclohe4ylamit* (15 g, O.13 moles) vras ad.d.ed. over a period, of 1.5 hor¡¡s to a refh.xing solution of ¡-tol¿i- aine (145 g) j,n sr.rlphure-free ¡y1ene (¡O tf) over d.egassed. Raney niclcel (frou, 62.5 g of al1oy). The solutj-on was filte:¡ed- and' èistj'Ile¿ as describeð to give (a) an oiL b.p. !0-15Tok6 mm (1.h e) containi-ng3- toluidine @" 5qù and. two other components, and. (U) lp(pmethylcyclo- (17"6 g), b.p" 14T-1aeo/t2 ¡r¡¡n which purified. by horyI)-p-toluidj¡re 'vas chronøtograpr¡y on 2OO g of alr.ur:i-na and. necrystal1.ized. from agueoris etkranol (tz5) to give colourless plates m.p. 5O-5ro158 (Found': Ct 82'7i H, 1o.3; N, 6o7. ctroHz.¡N requires: c, 82.7; H, 10'4; N, 6;f/')' lhe Il¡rnoro spectrun showed absorption d.r:e to a¡ al-iphatic rcthyl group at 9.10 (d.oìrblet, J ,, 5"1 cps) and an arorratj.c netkryl gncup at J.8O (singlet). The black so1id. residue (0.5 g) r¡ras not irvestigated"

(*¿) 1-Amj¡ropvriËge-vrith d.esassed. Rane.y nickel". - J-Lnünopyrid'ine (¡O add.ed. to d,egassed' (+O *¡ d.issolved. in sulphure-free benzene "¿) was -111-

and' Raney nickeL (fro* 62.5 g of alloy), the benzene evapolated-, the remainder ¡¡efLtxed. for 60 houts. The ¡ni¡cbuls was filtered' as previousþ d.escribed., and on d.:istillatj.on gave pyrid.ine b.po 50-600/\$ rrÛrt (1.0 e) ard. starting material boPor 140-150o/ZB *o (¡O e). lhe d'ark brcivm gave a :¡esidue (l ù was chromatographed. ori sjJ.icic acid. and ligþt yellorv solid. when eluted. vrj.th 2Úl e+,her¡\eflZ€ftêo crystallization from petroleum ether (b.p" 6O-gO0) gave yellow needles (O.O?5 g) m"p" 131-1320 1rit.145 mop. 1J2.0-ti3.5o)o the rroln¡ro slnctrum sho'¡¡ed absorption (Uroaa), four arøatic protons at 3"AO for'four protons (rv-n) ^t 3.87 (ao,;Ulet, J r J cps) and. tlvQ aromatic protons at Z.OE (tripttt, J o 3 ops) '

(otii) th sed.

hexaneo J-Ami-nopiperid.j¡re (Zl ù was ad-d-ed' to a mjxtu¡e of a1loy), metlgrlcyclohexarre (q¡ n¿) an¿ f,.egassed. Raney nickel (trcn 62.5 g of

and. then reflr¡ced.- for 50 hourso This was filterred' as befo¡e anfl the sol- vents evapor:ated. leaving a d.ark tarry flâsso Extraction of thjs with ether, s\raporation of the ether, and- d.istitlation of the residue gave (a) 5- 176- anr-inopiperi.d.ine b.p. 8Oo/14 rmr iO.+ S) ana (b) a yeJJow oil boP. , flgo/l4 run (9.i+ g). The black :¡esidual tar (8.1 d *" chromatogra$red. (U) on a}r¡¡ryj¡ra but no pure compounds'were isolated.. The yellow oil was pr¡rified. by d.istilLation to give 2r2t-bLpLperidyl b.P"¡ 180-180'5o116 o^ q;'it.155 b.p. z59o)" The mass spectrum shov,red a molecr¡-lar ion at rde 168 (T/ù *ra an (n-l) pea;r- (5V/ù. (x'or:nd'z c, Jo.7i H, 12.2i N, 17'3' calc'

for C.OttrONZ : Q, 71o4; H, 12"Oi N, 16'7fr)" -112-

(xviii) 1. cvc]. v¡ith d-e oas sed Ranev n:i eì

rflas add.ed. to d.egassed. Raney niekel (from 62"5 g of alloy) and' ¡efJr¡ceô

for 50 hours. Recovery of the prod.ucts as before and. evaPoration of the solvents left a d.ark purple so1id. (1"5 ù vrhich was chronatographed' on alr¡n¡nao Elution with hexane gave s-eyclohexylaniline (zJ g) id'enti- fied. by its j:rfrared. absorption and. gas ckrromatograpþ. Etl:et/hexane

eluants gave trùrenazíne (1"8 g) recrystallízed. from hexane as apricot yellow neeùlesr ß.po and. rn:jxed. m.p" 1J2o, and. trans-1 ,2r3r4rl+at5JOrlQa- octalgrd.rophenazine (0.5 g), crystal],ízed. from hexa* ": colourl-ess needles, ûr.po þ5o (Líf"tr56 l56t). (nouna: Cr 76"4i H, 8.4i N, 14o7. calc. lor cr,J7,rdz, a, 76"5; H, 8"6.; Nt 14.flo)" The mass spectnrm (O.29 showed. a molecular ion at uy'e 188 ßqù. o-Phenylened.iamine e)

uras eluted.'¡rith e1i,inanoL/r¡exane.

(*i*) nicLrel in xvlena* - o-Pher¡ylened.iami$e (21 B, 0.2 mole) in sulph¡u'-free xylene (fO tnf¡ v¡as ref}¡red. qrer degassed Raney nickel (frlom 62"5 g ot alloy) an¿ cyclohe¡ylarnine ß3 g, Qo53 mole) add.ed. over a period- of one houro Âfter 50 hor:rs reflucing, the solut1on was filtered- and. d.ístiLled. "as previousþ descrÍbed., giving aniline, b.p. 8}-g5o/þ rm (7"9 g)¡ 9- toluid.ine 85-V5o/15 ,*n (6"5 g), Aicyclohexylanrine b.po 135-1¿+00/15 nw

nm (2t.5 g), aJ-J. ç'e.,1 e), á N-cyclohe:ryIaniline b.p" 1!0-X51o/þ char¡acterized.by gas ckrrornatography ar:d. infrared spectra, The black -113-

so3.id. r¡esi-due (¡.9 g) rsas chror¡a.togra¡ùred. on alurrj¡ra which yieJ.d.ed. diphergrlamine (O.68 g) m.p. and mjxed. m.p" 5l+o, carbazoLe (O.et g) m.p. and mixed. m"p. 243-Ð+4or.n¿ o-pher¡rlened.iamine (Z.l+ g).

(**)

nickel in xvlene . - rn -Pheqylened.iarui¡e (Zt ù ,¿ras treated. w:ith degassed. Raney ni-ckel and cyclohe:çy1a:n:ine (ll g) in sulphure-frree rqylene as in parb (xix) " Chrun,atography of the c:rrde fiJ-tered. reaction ulircti.rre on alurni-na gave cyclolrexanone (0"25 g) o characterized. by íts 2 ]r d.initnopheny$rd.ra zot:re, m.p. and. mixed. m.po 1620 , and. N-cyclohe>çylaniline (g"t g) characterj.zed. by j-ts infrared. abso4gtion arrd. gas ckrrromatograpÌgr, both eluted. with hexane. F^ther/hexa,ne (1:1O) eluted. a d.ark thick tar

(16 ù which v,¿as d.istill-ed. and. gave (a) !-cyclohe4ylaniline, b.po 50o/0.6 r¡n (1 .5 (¡) a viscous yellow oil bop. 156-158o/'l.0 nur (to.z g). e) "n¿ The black residue (4.'t g) vras not investigated further. The yeIIow oil

(U) aecmposed to a black solid. before analysis could. be olctained.. The n moro s¡nctrum (CCÐ shorved. a broad. absorption for 20 aliphatic protons at 1.82-9.2, a broad peak (for,rr protons) al 6"77t and. three aromatic p:rotons absorbed. at 4.13-4"35 (mútiplet) and. one anomatic proton at 3.26 (triptetr'J o 7.5 cps)o the infraned. spectrr:n (ccrn) showed. peaks at i580, 3O4O, 2930t 2860, 1610, and. 1600 The ultraviolet absorption "rn-1o was similar to n-pher¡rlened.ia¡nine, but bathochronricalþ shi.fted. by I mu. -114*

(:o.i) ni"ckel in [v1ene" - Cyclohe4yl,a'rÉne (ll e) v¡as add-ed. to owr degassed reflrrxing ¡-fhenyleneaiaraine (21 g) in sulphur-free rylene 'vÍas Raney nicket as i¡l parb (xix). After !O hor:rs the cataþst removed', ar1] èistillation of the resulti.ng nixtu¡e gave (a) ani1j're b'p' 8O-85o/ 16 un (+ e), (¡) a mixtu:¡e b.P. '! 10-150o/16 rrn (to.z d of S-cyclo- hexylanil íne (2fl)r ad d.icyolohexylamine, (") $-cyclohexylaniline,

b.po 99-1 ozo/1o0 nrrn (7.1 e), (a) t-pher{r1eneôianri¡ee, subu-rnea 'ltutSoo/ (+'¡ ard' a bl-ack lo0 mm (o"+ e), (") a ye].low oi:. bop. 160-165o/1.0 nm e) J-iqui¿ residue (g g)o The black residue was shown by thin-layer chroma- tograpk¡¡ to consist mai-n3¡r of the oif (a)" Red'istilJ-ation of thj's oiI a pale yelLow ojJ, b"p" 16lr- gave !flr-ùic¡rcloherq¡rl-p-pheWlened:iamine as 165o/0.g mur, (rito159."p.55o) wrrich on stard.ing at rcom temperature for two hours turned. d.ark red., and. v¡as black af*ber one d.ay. the n.m.r' strnctg:n of the f:reshly d.istilled. sample showed absorption for four (fo'¿r aromatic protons at 3.6\ (d"or-,U1et, J e 2"5 cPS)¡ a broad. peak at 7"Ø pr.otons), an¿ a broad. absorption f¡rcm 7.75-9"17 fot 2Q aliphatj.c pnotons. the mass spectrurn showed. a molecrrlar peak at rde 272 (O.4" of, base peaÐ ' CHAPTER. ITI

S,ynthesis of monosubstituted. 2 22r - biPYridY1so -115-

Until the introd.uction ín 1956 of Raney nickel as a cataþst for the di¡r¡erization of pyrid.ine lo 2r2r-bipyridylr6 th" preprrati-on of ttris compourrd. a1d. its d.erir¡atives yras a laboriou^s pnoced.ure lsual-ly 5-:e- volving the U1l-nann reaction of halo-pyrid:ines w:ith copper cataly"t=160'161 With ilegassed. Raney nickel, pyri&ine couples exch¡sívely in the ø- position, givi:rg a relatively simple pathvrraf to large quantities of bi- pyni¿yl, gneatly facjJ.itati.ng further lvork on th-is s¡rsten. Subsequgntlyt thjs ¡eaction was ad.apted. vely successful\r to the s¡mthesis of s¡rone- 1 4 tricalþ d isr:bstit rrteô. 2 r}t-bipyridül"o îhj.s reaction rcas ljm-ited. by the fact that substituents which react with the catalyst could. not be incorporated., and. those with electron attracting prcperties gave much lower yield.s of the required' ai-"".145

Haginavrar162 àri. concurrentþ tr/raerler and c^ru1163 d.eveloped' a ræthod. of preparing 2r2r-bipyridyl-1r'lr-d.ioxide from 2r2r-bipyridtlr lrYiâich gave,

| ( arÊ- hence on nitration, 4¡,1+r -d.i.:ritro- 2 ,2t -bípyridyl-1 ,1 -d.ioxiae 6¡) , tjae ¡oute to a large nunber of d.isubstituted 2r2t-bípyri(y1s. Recently,

Case an¿ lru"r""164 have applied. this sa¡ne sequence of reaotions to tkre

I ,l+ st 2 iquino\rls preparation of ¡ 4r -C.isuìc ituted-2, -b "

NO 2

N \ / '/ 0 0 0

(6t) (64) -1tr6-

However, a much greater problem remained.'in that llr¡sJrrnnetrical or mono-substituteC. bipyrid.yls could not be synthesized' successfully from bipyrid.yr. Bursta:1trl'S in .¡2iB, showed. that brrcmj¡ration of 2121- bipyridyl at þ0Oo gave a mj¡cturre of 6-b:¡omo- anrl 6r6l-aibromæ2s2r' bipyridyl i.n poor yield.so Pherlyllithiurn r¡¡as also forrnd- to sr:bstitute j¡e the S-position to give 6-pher¡y1-2r2t-b1pyñdylr166 an¿ 4-met¡1y1,'2n2t- bipyridyl was reported. by Oj-slak' ,067 .o*g soclio-pyrldine and. a quate:r- nary salt of $-picoline-1-oxid.e, but no yield.s or methods were d.escribed" The onþ other examples of mono-srilcstituted. zt2r-bipyridyls har¿e been

æporbed. by T-,eontr ev, Stroshchenko, Mtangutova and' Da{ykov'¡68 lvho mea- snred the electron:ic absor¡gtion spectzra of À,'cyano- and- ¿rcaròory-Zt/t- bipyridyl, but nade no mention of their sorLrce. Hence, the isolation of i-nLtrc-2r2¡ -bipyri$r1-1-oxiae (6¡)

by SiasseTo *" of great irnporbance as tÀe fjrst najor bzeak-througþ in tlre preparati.on of l+-substituted. 2r2tàipyridyls. Bipynidyt-1-oxide (64) had been reprted. before by Murase ,"' * a by-pnod-uct from the prepa::a- tion of 2s2r-bþyridyl-'N11r-d.J.oxide, but he ignored' the mono-oxid-e, apparently not realizing its potential, and developed. cond-itior¡s for a greater yield. of the dioxide" Sasse oxid'ized. Zr2t-bipyri(yl at 5Oo wittr

hydrogen perþxj.d.e in acetic ar;id-o arid. r:sjng a nptiiod. similar to that of

¿en Hertog a¡¿ CorbierlTo ,=*o.r"d. the excess acid.s ar¡d. òirectly nitrated' the crud.e nrjxtu¡e of bipyrid¡r1.4{-oxid.es with fum:ing nitric acid- and. sulphuric acid.. this project had., as its airn, the synthesis of a variety of -1'17-

j-n pzeviousþ ur:.lgrolrn lrsr¡bstitltteð, 2 r2-bipyri{y1s arrd. their N-oxicles r ord.er that their inf::ared. and. ul-traviolet spectra and. their ¡ù{a values cor¡ld. be rneasu¡edo

the mæcimun yieLd. (zl%) of Þni.tro-2r2r-bipynid,yl-1-oxiae (65) was obtaj¡red. with the oxid.ation proceduæ at 5Oo for 12 hor¡rs, followed by nitration as d.escribed. above" By-prroducts includ.e a 1So yield' of

4rl+f -d.j.nit.rc-2r2r-bipyrid¡rl-1t1r-d.ioxide (6Ð, 3V. yj;e]:d. of lrnitro- 2r1a-bípy¡*idyl-111r-d.ioxiae (66), and. a 7/o recwery of starüing nateriaL.

NO 2 2

N / \ / 0 00

(65) (66)

carrying out the oxidation at a lov¡er temperatune or for a

shorter ti.ure gave decreased. yield.s of bipyridyl-N-oxid.es ar¡l a greater r€covelxr of Zr|t-bipyriclylc Higþer temperatures ðrrring the reaction jnc:¡eased. the yields of di-N-oxides¡ while longer reaction times ktad- litt1e effect on the cn¡eral-I yield's. þNitro-2r2r-bipyridyl-1-oxi¿e (6¡) was the key starti-:ng rnaterial to all compounds in this series, but as the nitro gloup is not a veqy good. leaving group (compared. u¡ith halogens for example), and. as the conversion to lrchlorc-2t?-t-bipyridÍl-1-oxid-e (62) ruas in good' t\ -1.!3- yietd.s, most other d.erivati'yes vÍer\-- pr.epared. froln this }atter cornpound. The chlorine sr:lcstitution of the nitnr grìlqg proceed.o,l snoothly u;sirlg acetyl chlorid.e by a method. sim:il-ar to that used. by Maerker *d' Cor. 1163 wÌ::ich 1l¡as fol¡nd to be also applica'l¡Ie to the prepara'bJ-on of \'bromo-Zr2t ' bipyri{y1-l-oxid.e (672 X o Br) by using acet¡rl broraid.eo lhe only com- pourrd. not prepared from the ÞchIorc d.erivative r,rras 4-benzyù-oY.y-2r22- bipyridyl-1-oxid.e (68) (See Scherne 18)o He:re, better yields v¡ere obtained. by substitution of the nitnc group with sod.ium benzylo>:id.o in a reac'¿ion si¡r:lLar to that used. by otrt:-ai171 in the pyrid.j:ne serieso this sr¡bstitution, and. aLl others vrith soctirun alkoxid.e in alcohol on the bipyrid.yl-1-oxid.e system, proceeded qrrite smooth-ly ard gave good yield.s of the Þalko>ry-Zr}t-bípyrid¡r1-1-oxi¿es (69)o Ho','rever, in early experiments i¡r'lvtrich an excess of sod.ium uas useC., pnotlucts were ab,rays contam'inated. with þaIkor¡¡- 2 rTt -bipyri{yl (lO), prresr-u'nabþ becar¿se tlee N-oxid.e was red.uced by the sod.iurn-a1cohol reagento this was expected in the light of work by Schrveizer and.0oNei1l.tr72 ,lno deoxygenated. pyrid.ine- 1-oxide with soctiwa methorid.e i¡r rrethyltrichlonoacetate" Using an ec¿ujmolar ¡atio of reagents, the retluined- N-o:;id.e could. be isolated. and. purified. without arry d.ifficulty" One attempt to

! syntlre s i ze þa1ko4y- 2, ?-t -bípyridyl ( 7O) f ront þnit:rc-2, 2 -bipyridyl-l * oxi¿e (65) in one step vrith a large excess of soclium methoxid.e, gave onþ a mlxtune of starbj¡rg material-¡ 4-methoxy-2r2-t-Éipyriqyf (Zo), its

1-oxid.e (69) .ana several other compounds '¿hich were d.ifficult to separate, -119-

0cH NO NO zPl^ 2 2

N / o 0

(68) Gs) Qs)

s, cH x OR ¿?h

/ / / 0 0 0

(zt) (62) x = 01 or Br çeù

2

N N N ,/ 0

Qz) fto) R s Me ortrt Scheme 't B.

, .S,od.ium benzylsulphid.e vvas an even better nr¡cLeophiJe than alkoxid.e iorrs, and' the yield' of J'¡-benz¡rLlltio-2r2t-bipyrid,yL-1-oxid'e

(7t) was 8(o, compared. with 5ffi fæ tìre ethoxy (6g; n = at) anà 43% for the m.ethofy (6g; n = Me) derivatives. The sr¡bsiitution of ctrlorine with d.j¡nethylanine p:sceed.ed -120-

.very smoothly in a sealed. tube at looo to give a hyd:ochlorid.e salt of the d.imethylamino derivative" This rtras convertecl to the free base using anrnonia, but this ir-d.j-rnethylamino-212!-bipyrj.dyl-f -oxicle v¡as aI'yïays

conta¡n:inated. w:ith vrater, even r'¡hen crystallized fn:m petroleum e1ùer.

Frorn anaLJ¡sis figures, freshly crystallized prod.uct appeared. to contain approximately 1.5 rnoles of vrater, vrhile a sample rvhich vras d.ried- by

stand.:ing u¡rd.ei reduced pressure for a few hours or by wazning, contained.

about one mole of .l'ratero However, this vrater content r/vas never co:ostant

enougþ to give a consistent analysis. Ad.d.ecl evidence for this bomd. r¡'¡ater

is given by the ncrrroro spectrao lhe r¡ntreated. sample shov¡ed a sharp singlet at f 7"06 (3 pro-bons) coxnespond,ing pneslunably to the 1"þ moles of water, while the treated sample had. this peak shifted. d.orvnfiel'1 to f 6"22 (2 protons) and. was much brroad.ero The natu:re of this water js still rx¡lsrow:ro Confirr.ration of the stzucture of 4-d':imethylam)'no-2r21' bipyritì¡r1-l*ox:ae (72) is prov.ided by the IJ.¿III..ro and. mass spectrtr.o

D.e-oxygena,ciol of these bipyridyl-1-oxj.d.es 11-¿s achieved ej-ther with phosphoncus trichlorid.e in chlo:rcforrn or by hyd.rogen over metal catalysts. h-Nj.tro-2t}t-bipyridyl-1-o:dd.e (65) vlas converbed. to 4-rritrs- 2r2r-bípyUyf (7¡) in good yieias using phosphorous trichloride .irith a

method. sjmilar to that of Maerker and. C*""r16J n** 4r4t-CirÉtrp-2s}t- bipyridyl-1r'lr-d.ioxiae (6Ð. Hov¡ever better yield.s were obtajned. with

tlie mono-N-oxid.e l¡ecause of i'cs greater solubi-Iity in chlorr¡forrno

l¿.Clilolo-Zr2lir.ípyri,lyl (7+; y; = CI) vras pnepared. very con- venientþ in one step frrcm )+-nt'brp-2r2¡-bipy::i.{y1-1-oxi¿e (6¡) Uy

ref}.ucing j¡r a n|xture of pltosSfro:rcus trichlorid'e and' acetyl cl:loride" -121- this reaction gave about 5Ol yi.e]'ds and r/rras also appli.cable to the

NO x lûtle 2 2

N N N / X c.CI or B-r , o (65) (7-) Qs)

lüi OR co lú 2 2

Qt) ( zo) Q6)

S)cheme 19. analogous bromo compowrd.s using phospho¡ous tri'l¡romid'e and. acehy:-. brþmid.eo lhe Þchloro-Zr2tüLpyrí-dyt (7J*) was then used. as a convenient starbing saterial for several other compound's (Sctreme 19).

[-Ethoxy-Zr}t-bþyridyl (70; n = Et) and' Þ¡netinory-2r2r- yield.s by srùstitu- bipyrid,yl (70; n ' Me) were prepaned. in reasonâb1e tion of the chlori¡re group by sod.ium alkoxid.eo Hovrever, a more con- venient method. of pre¡nration of these compowrds involved. treatrnent of Þa1ko4y-2r2t-bípyridyl-1-oxid.e (69) with w-7 Raney nickel und.er one -122- atrnosphere of k{yd.rogen, although l+-ethor-y-2r2¡-bipyridyl (70; R = Et) was onþ obtained. in fi% yield. because of &ifficulty in purjfication" '!-oxj'de /a'Benz¡rtoxy-2r2?-bípyridyl (Zó; n = Ph) v,as prePared frrom its (68) ¡V a sjmilar hyd.rogenation. Conversion of ,lrchl-o'1o-2r?-8'bípyrLayL (71+; X ' CI) to 4* ðìmethylarni.:nc-l2 r2t-bipyridyt (lù by aqueous d'jrnetk¡rlam-i¡re solution in a sealed.. tube occu¡xed read.ij,y, to give the hydrochloride salt v¡irioh was Ïgrclrol,:yzed, to the free base with ammonia"

A ttempts to p nepare ta-cy an42 r2r -b ípy rid.yl using S oùir:nr cyanid.e in d.imethylsulphoxid.e on Jschloro-2r22-bþyï:idy1 (l+ ; x e cl) failed.'

Even thougþ the solvent had. been d.ried. and. d.istilled. from calcium l¡yd'rid'e, the ody product isolate¿ was ,lrcarboxam:1d.q.2 ,2s-b5;py-cLdyl (76) ¡ Pre- sunably fozrned. by hyd.rotysis of )a-cyzno-2r2¡-bipyriftflo It should. be straigþtfo¡wanl to convc¡-b tlús ar¡rid.e group j¡¡to both þcyøtiæ2r?r- bipyridyl ar¡d. Þcarbory-Zr?-t -bipyrid.yl which ï,.ere neported' by Leont¡ev, 68 by d.ehy

2 r?t -b:,pyridyt (77) and. its1-oxid.eo lVith,l¿-ilttropyriùine-'l-oxide¡ Ochiai17l .t*t"" that the N-orcid.e fr¡nciion was moic13 stable to red.uction than the nitr.o Brcupr eicept wrd.er acjdic cond.itiorrs. Usj¡rg chernical r"ed'ucing uethod's, such as ti¡¡ in acetic acid', the a¿o4y arÊ' azo d'imers were for¡ned. exclusi.veþ" lYith catalytic red.r:c'r,ions over paIlaùium horvever, þarninopyridi¡re v¡as the product wlren hyd.nochloric acid' v¡as the -1?5-

solvent, md l¡-aninopyrièine-1-oxid'e was obtained' in etJranol' l+- azo Nitr"oquinoline-1-oxid.e shor,¿efl. a greater tenclency to form llne d'imer, apparently due to greater steric factors preventing cata-lytic recluction of the azo li.nlege" ' Haginawal62 to oÌ¡tain a Lgrd'razo compotxrd with an N- "l^:r¡o.d. oxid.e fi:nction j¡rtaot from the' reduction of 4rJF¿initro-2r2r-bipyrj-d¡r1- 1r1t-dioxi¿e (6¡) over catalysts in t¡rd.rcchlor:Lc acid', but rnade no mention of a¡y a¡lino compor:nd.s obtained" The æd'uotion of 'lrnitro-J- picoline-1-'oride by Rao175 vatnRaney nickel gàve consid'erable quantìties

of azo compowrd.s, but good. yielcls of the amine weæ obtained' with palla-

dir.¡r¡ catalyst in aoetio acido Consequently, r,vlæn the red'uction of, lrnitro-2r2r -bipyrifirl-

out with W-7 Raney nickel i'n ethanol, it was 1-oxj.de (6¡) '¡vas carried not surprising that a nr.ixtr¡re of vdnat appeaæd. to be IrIt-bis(t+-2t7t- bipyridyl)*i:idae (Zg) an¿ the correspond.ing azo4y compow'6. (Zg) ut"" obtained." However, red.uctions carrieè out over pallad'j-um on 'calbon both inethanoland'aceticaciclproduced.avelysini]-arr¡.jxtur.e,fromwhich the no asLi-no comporrtd.s 1uere obtained. Maerker and' Case155 acirieved'

| red.uction of 4¡4r -d.inj.tro- 2r2t .*ii:pyridyl-1 ,1 -¡ri oxiae (65) to [r'l¡t - d.ia¡¡rlno-2r2r-bipyrid¡rl v¡ittr inon in acetic acid'o Equivalent cond'itions witlr ¿rnilro-2r2t-bipyridyl-1-oxid.e on\r pr.od.uced' a purple water soh'¡ble substar¡ce, apparently an irrcn complex of the bipyridyl'

B,ed.uction with flo pa;-¡.adíum on barium ca¡bor¡ate in ethanol -1ilf

N N

(ze)

o \ I N -N

N

Qg) gave a pale yellow solid. in reasoriable yieJ'cl. the stn¡ctr¡re of this ccrmporr¡d. has been assigned. as l¡--(¡gr-1r' ,2ì-.d.Stgrd.nopyridyl)-2¡2t -bipyriQyl (gO) on the basis of the mass spectrao H

II

N N

(eo)

The rrass spectra shows a molecular ion at 235 and. a stable (¡¿-t) peal< (W) correspond.J.ng to the aromatized. systemo The nom.r" sPect:¡¡rt shows the two alipbatic pr"otons ad.jacent to the tertiary nitrogen as -1Zj- b¡pad. peaks at 6.55 a¡¡ 7.Q5. l¡..,Aruino-2r2r -bipyridyl (77) uas final-\y obtai¡ed' by rred.uotion of Þnitro-2t21-bipyridyl-1-ocÍcte (6¡) wittr sod-ir¡¡n borol¡ydnld.e i¡r aqueor¡st rnetha¡rol cata-1yzed. by a trace of pallad.ium on carton using a nethocl sir¡.iJ.ar Neilson, ltùood., f'{ytie.174 It'is inteæsting to note tnat to "rra altlrougþ these authors olai.n thià ¡¡eaotion d.oes not proceed. via azo compound,s, small quantities of the a;zory oompound's (Zg) '','t"" cbtained. from this ¡red.uotion. -'à26-

EXIÐR.Il'/EI{1l\T,

1o General. Nuclear magnetic resonance (nomor') spectra were deternÉned' witLr a Varian DP.6O spectrometer, calibrated. relative to tetn¡¡oetk¡rI- silar:e using sid.e-bar¡d. techniqueo Mass spectra 1lrere ¡æasr¡¡ed' with an Hitachi perki¡¡Æl¡¡er RMU-6D sj-ngle foeuisir¡g mass speotrometer. Infra¡ed. spectra were measured. with a Perki¡r-E)srce 1JJ or 237 spectrophotometer. Anaþses .were caried. out by the Australian M:icroanal¡rbical Se:rrice t trÁe1bor¡¡rre.

2. O4id.{El"on and. Nitration of 2"2r-biPgridvf"

Hyd.:rogen peroxid,e (lE ,tt;'0"66 mole s of J6l agueous solution) r¡ras ad.d.ed. with::apid stirring to a co1d. solution of Zr2tùipyridyl (15.O gi 0"096 moles) L\75 ml of A.R; glacial acetic acid' and. hoated' at 5Oo (-t fo) for 12 houzs with occasiorraL shalcing. E¡ccess peracetic and acetic acids

were rernoved' from the resulting ligþt J/allow liquid by d'istillation at

20 nm pressure on a boiling uater*batho The thick oiþ residus uras cooled. in an ice/saIt-bath and. quiclcìy d.issolved. in 40 ml of concentrated' sulphuric acid (occasionalþ thi-s ad.d.ition was rrery exotherrnic)o A mixtr¡¡e of concentrated. sulphuric acid. (l+O mI) and. fr:n:ing r::itric acid'

(60 mf) uras add.ed. to the solution, rn¡hich was then heated. at lOOo for two hours. The cool"eê acid.ic solution uras poured. onto 2OO g of ice and'

ad justed. to ÈI 5"5 ,r,rltr. sod.ium l¡ydroxid.o and sodium bicarbonate söluti.on's"

lhe or.ange-b:rovyn precipitate was filteæd. off and ext¡acted' with boiling' -127- ethanol (4 x Z5O *f). The remaining yellorv solid. ,¡ras l+r4'-dinitro- 2r1t-bþyridyl-1r1t-d.ioxiae (2.5 g; 'lTft) whích crystallized' from etharrol as yeJJow needresr ilopo 27i-27+a çtit.16' "7rro). Ihe ethanolic extract was concentrated. to about l¡OO m].t and' on cool"ing, yield'ed' Þnitro-2¡2t-bipyrid'y1-1-oxide (4"4 g; 21Y") as ye|low neeilles, mop. 1850. This samp3,e had. the sanp melting poj4t and. i-d.entical i:rfrared. spectrarm as a sample characteri zeð. by St""u.7O lhe aqueous nesidue (É 5.5) was basified. with ammonia and. then continuous\r extracted. with chlonoformo The d.rj-ed' chloroform ex- tr:act yÍel¿e¿ a d.ark red. solid. on evaporationo Extractj-on with petrolewt ether (b.p. 60-800) gave impure 2r2t -bipyridyt (1.0 g; 7/")" The remair¡- ing solid. vras crystallized. from ethanol to give þuitræZr2r -bipyriSrl-

111f -.r.åioxide (7.2 g. 3l*/"), pluif5.eð further by recrystallization from water as fine ye|low needles¡ IrI,Pj 243o" (Ior:¡d.: Cr 51.4; H, J.1; N, 17.6; Or 27.1+. CfOHf¡O+ rraquires z Ç, 51.5i TIr 5o0; N, 17.8; o, 27"5%)"

7 (l) - þNitro-2r2r-biPYri-4yl-1- oxid.e (l.O Ð and. acetyl chlorid.e (ZO mI) were refluxed. on a boiling waten-bath for two hoursr and. then pouned, onto l0 g of ice. Ihe aqueou.s solution was neutralized. with 1@ so&iun kgrd.r-oxid.e solution and. extracted. with ck¡lo:rofo¡m (J x 5O mf). The :¡esidue obtained on evaporation of the chlorofo¡rn was cry'stal.li,zed. from petroleum ether (b.p. 6O-8O0 ) to yield. -1?8-

needles, ,lrch-loro- 2 r2t -bipynidyl-1-oxid.e (O.75 g, 7f/") as colourless mop. 9þ980. (Found: c, 57.5i tI, J-6; N, 1J.5. ctdi/zæI ¡equiæs¡ C,58.1i H, 3.4; N, 13.6%)"

4-Ct¡-loro-Zr2r ùípyrid'yl- (ä) [,Ðthoxy-2 "2r -bipyridvl-1-oxi-d.e, - l-oxide (0"5 g) was ,lissolved. in'rsupend.r5y'r ethanol (tO mf) and. fresh\r cut sodium (O.Oe d ad.d.ed. The solution was reflr¡ced. for one hour, and. then evapor"ated. to dryness. The residue was ext¡acted. v,rith petroleum ether (b.p" 60-801 (e * tOO mI) rdoichr on concentration and' cooling, yield.ed. uhite neeðLes of Þethoy-2r2'-bÍpyridyl-1-oxid'e (O.Z g; 57")" Recrystallization from petroler.m ether gave pure prcduct, m"p. 8J-g4o, (!or:nd.: c, 66.5i Ht 5.5; N, 12.7. 'c,lplÐzoz requires: Qr 66'6; Hr 5"6i N, 11.gr/,). the picrate crystallized from ethanol as yellow neeèles,

mop. 153oc.

(iii) ÞMethoxy-2,2r -bip.'¡rid.yl-1-oxid.e" - This v¡as prepared. as color.rrless needles¡ D.P¡ 117o, irl 1ú% yie1d. by the same rethod as that d,escribed. for Þetho:¡¡,-2¡Zt-bipyridyt-1-oxid.e. (founaz C, 64.6; H, J.2; N, 13.5. Cl1H1oNzOz requine's: C, 65.3i Hr 5.O; N, 13.y/") o the picrate crystarlized' from etha¡ror as yerlorv neeôles, Irlopo 1660' Found': c, l¡J'o; H2 3.2. tlfl¡*¡O, reQuir"es: C, 47"3; H, 3'o7o)"

(i") À.Ã enzv]-:tjhj-:o-2. 2 | -b ipvrid,yl-1 -oxid-e. - lv'Ch1o nc-2 ,2r-bipyriqyl-

1-oxide (Oú5 g) was ad.ded. slow\r to a solution of so&ium ben4rlsulphid.e -129-

(from 0.21 g of ben4ylme¡captan ar¡å sod.ir¡n ethoxid'e from 0.0/al g of sod.ir/m in l0 ¡nl of rrsuper.-d.r¡/r ethanol) and. then nef}¡ced' for one hor¡-r. 0n cooling , J g of solid carbon d.ioxid.e was ad'd.ed. to the yellow liquid', which was filtercd. and. evaporated to d¡ynesso The residue vras d'issolved. i¡r cSloroform a¡rd. centrifuged. Q¡¡ svaporation of the drl-orpform solution, a d.ark red, liquid. containing prod.uct and. benzylmereaptan remained. The latter was remove¿ by steam ù-stíI1ation, leari:ing a yellow solid' r*tich was crystallized. from etþI acef,ate to give )a-lben7¡!thíæ2r21-bipyri{y1-1-

ori¿e (0.ÀO gt 8g1á) as shirSr yeJ-lovr platesr R'P. 139o. (For:rld: C, 69'8i H, 4.8; N¡ !.Jo requires: C, 69.4i H, J+'g; N, 9'5%)' "lll+*16

l+'€hIoro-2r2r (") J...Dime -?-r -1)i-uvridvl-1-oxid.e " - bipyri{yl-1-oxid.e (0.50 g) vras suspended ín 35% w/v. aqueous d'irnethylamj-ne (fO nf), and. heated. in a sealed. tube at lOOo for 24 hours. The aqueoi:.s solution vfas evaporated. to d.ryness, the residue d.issolved. in chloroform,

ar¡d. ammonia gas bubbled. througþo the præcipitated' ammonium chlorid'e was

removed arrd. the chloroform solution evaporated. to dryness leaving a brown sotid. whi-ch was extracted. witir boiJing petroleum ether (Z x ZOO mt)' This

ext¡act ïuas concentrated. to about 50 nlr from which the prod.uct cI$S- talljzed. on cooling. Surther crystallizations from petroleu¡¡ ether gave 'On yellow need.Iesr ffi.p. 15to (pfrase changes at 8Oo and. 1O5oI. d,ryi¡g

at 65o/O"J run for 2 hours over 1ùrosphorous pentachlorid.e, no phase

changes wene obsertred.o -130-

The nom. r. spectrum (COCfr) sho',ved a di:netþylanrino absorption at 6.il+ (siriglet) r seven aromatic protons from 1.12 I'o 3'18, and' a skìa¡T singlet at 7.06 cortespond.ing to three prctons. The d'ried. sample had- the

same sPectrum except the latter absorption was shifted' to 6'22 (z protons)

ar¡d. ,¡¡as broad,ero The nass spectrum sho'¡¡ed a molecr¿lar peak at ty'e 21J

(1/") arrd. a strrcng (r"r-te) peak at n/e 199 Qg/).

(vi) À,Ð erøylox:¡-2,2t -Jipyridyl-1-9lc:Uþ, - ÞNitro-2 e2r -bipyrid¡rl- 1-oxid.e (0.50 g) was ad.d.ed to a solution of sod.ium ben¿¡rloxid,e (prepared. from 0.06 g of sodium in 15 nL of ben4¡! alcohol), and' left to star¡l for eigþt hours. Excess benqyl alcohol v¡as removed. by d'istilLation ar¡d' steant d.istillation, and. the d.ark red reslöue ext::aoted. with hot petrrrleurn ether, 'which yield,ed. on cooling, pale yeJJow neeèles of )+JoerryLory-2r2t-

bipyrid¡rt-1-oxj-der ß.p, 138-11+Oo (O"23 et 56%). (For'maz A, 73.4; H, 5"1; N¡ 9o9. Ctft+NZO, reQuires: C, 73.\; tL, 5.1; N, 1O"1:/o)'

(vii) à,Ðromo-2"2û-bipyri4vl-1-oxide, - this was pr^epared. as colou:r'

less needles, m"po 115o, ín W% yiel¿ by the same method- as d.escribed' for 4-clrlon¡-2r}t-bhpyridyl-1-oxid.e, r.using acetyl b¡o¡nid'e in place of acetyl ctfloriðeo (nouna: ct )+7.9i Tl, 3"oi N¡ lOo9o Cfffz@requires: C, 47"7i H, 2"8; N, 11oryù.

4" (i) l+-Ni fuo-2"2i -bípyrid.yl" - lrNitro-2 r2r'bipyridyl-1 -oxid'e (¡ ( l.O g) v,ras add.ed. to a solution of phosphorcus trichtorid'e d in -1 )tr- arùgrd.rrus chloroform (¡O n¿), and. ref}¡xed. for one hour. This was pouned onto ice ard. left to stand. for ei,ght hourso The rnixtu¡s was then neu- t::alized. and. ext¡acted. w'ith chlonoform vrhich, on evaporation, gave a yellow residue of crude pnod.trcto l¡-Nitrrc-2r2r-bipyridyl (0.75 gt 81%) was orystallized. from ethanol as colourless needfes r il.P. 118o. (n'or:nd': Cr H, 4.0; N, 2oo5o requir:es: Gr 59.7; Hr 3'5i Nr 2O"//')' 59"9i "tOnf¡OZ

( 1 g) 2 2t -bipyrifrrl-1-oxiae . O (u) J¡-thlonc- "21 -b1pyrid;fl"-- 4-Nitro-2 r acetyl chlori¿e (ZO *f) and. phôsphorous trichl-orid" (5 ml) were refLr:xed' j.ce for one hour. The solution was poured. onto 100 g of and' neutralized.

The mixture l.fas extracted. with ctrloroform, the chloroforrn evaporatedr and' the d.ark residr¡e extracted lvith petroleum ether. The petroleum ettrer extract vvas evaporated. to dryness asL the remaj¡ring solid' sr¡bIi¡ned. at as 6oo/o"z ¡rmr to give pure ÞchLoro-2r2t''bipyridyl (O'+g gt 5r%) colou:r- Iess need.Ies, m.po 8¿-85o. (Foi:nd: C, 62.6i H, 3.7i Nr 14'2' Cld/zoL requines: a, 62.gi H., 3"7; N, 1)+"7o). al,te¡natively, the product rny be purified. by crystallizatíon from petroleum ether (b"p" ,l.0-600).

(i,ä) 4,8romo:2"2t-bipyridyl. - Th'is was pnetrnred' in )ß% yield. by the same rpthod. d.escribed. for {r-chloro-2r}t -bipyrÍdy} using acetyl

bronui.de and. phosphorÌrus tribronuid.e in place of acetyl chlor:id'e and' phosphorous trichlorid.eo]¡-Ðrrcrno-2r2t -bipyridyl crystallized. fzpm

petroleum ether (b.p. 40-600) as colourless needlês¡ m.p. 52o. -11?-

(founa: G, JZ.O; Hr 3.3i Nr 12.0o Cfdff" reguires: C, 51'1i H, 3'Oi N, 11.1o). Ihe pj.or"ate crystallized- frorn etha¡tol as yelJ.orv need.lest rr.po l7\-175o" (Foturl: t, 41r9i H, 2.2; N, 15.5. ClgHfON¡Of " noguilles: C, )+1.4; H, 2.21 N, 15"1%,")

( iv) À-Ethe)qlr-2,2i:&iørqrdJ-1o - ÞÐthoxy- 2 r21 -bípyrid¡r1-1-o:

N, 16.Y/") .

(") o - Ihj-s rruas prepared' from À-chloro' 2¡Zt-b];pyridyl (0.5 S) and excess soclium (0.1 Ð in methanol by the sane method. d.escribed. for 4-methory-2 r2r -b ipynt{yl-1 -oxid.e o lhe product crysta3lized from petroleum ether (b.p. 40-600) as colourless needJ-es (o.zh gt 4f/.), mopo 610. (nor:na: c, 71o2; Hr 5.6; N, 15.0. G'1HIONZO requires: C, 71.0; H, 5.4; N, 15"Q()" -,|.13-

("i) - [-Chloro-Z r21 -bíPYridYI (0.50 g) was suspénd.ed. )n 3y/',tr/'v aqueous d'imethyla¡nine (tO mf) ana heated. in a sea-led. tube at loo for 12 hou:ls. The aqueous solution was evapor-ated. to d.ryness, the nesidue d.issolved. j¡r chloroform, ancl a¡nmonia gas bubbled. througþ. Precipitated. a¡n¡r,oniüm chlonid.è was removed., the . chloroform solution washed. with water, dríed, and. oraporated to drXrness.

The resid.ue crystaIlized. from ¡retro1eum ether to give -C'j¡nethylaníno-?r?r' bipyridyl (O.Zt g, +ú/.) as pale yellow needlesr IIroP" 1COo. (nouna: c,72.7i H, 6.8i N.2 21.2o cyf,lfs requires: at 72.3i H, 6.6; Nt 21 '4")' tshe picrate crysta]lized. from etha¡rol as ye1lo'rv needles, m.po 2OBo" (!or:nd.z C, Jo.Ji lI2 3.8i N, 19o1o Ctdt6NgO, æqr'r'i'res: A, JO.6; H, 3.8i N, 19"6%).

(vii) ù-GaJþoxamid.o-3.2r -bip.yridyl" - To [-chlorc-z tzt -bipyridyl (t.O e) d.issolved. in climethylsuJ.phoxide (t¡ mf) (ariea arrd. &istilled. from calcium hyd.rj.de), was ad.d.ed. sod.ium.cyanid.e (0.5 g). This solution was heated. at 1BO-190o for eigbt hours. After cooling, wate'r (¡O *f) ether (l r¡vas add,ed., and. the solution ext¡acted. with " lO,'mI) " lhe ether solution was washed. with water (Z x tOO m1), evaporrated. to d.r¡rness, anrl the residue extracted. with etha¡roIo On concentraiion ancl cooling of th:is etLra¡rolic solution, ,lpcarboxamid.o-2r2r -bipyridyl crystallizecl as ¡nre yerlow plates (o.29 e; z8/á)r ûop. 2oooo (For:na: c, 66.5i H, ,1r.8; N, 20.8o cttngN,o requires: c, 66.3; H¡ 4.6; N, z1.il%)" '11+

("i¿i) - This was prepared frpm ÞbenzyL- oxy-2r2.-bipyridyl-1-oxide çO.25 e) and. fho¡$on3us trichloride, by the sane method. as d.escribed. for Þnittp-Zt}t -bipyridyl. l¡,$enzyloxy-|r/t- bipyridyl (0.t8 gt 7T/ù cr;ystaTJízed from petroleum etl¡er (b.p. 4cr-600) as.colourless needles¡ Inepe 91-920o (Fow¡a: gt 77.\'i H, 5.5i N, 1oo2o Clft+NZO reguires: Cr 77"8i Hr 5.\-i N, 1O"TÁ).

à Red-uction of Nit¡a com'Ì¡otrncls" ¡_b (i) and. A- (¡O ad'd'ed' snspension of 1(o pallad.ium/carbon (O.tO g) in water ^f) was (U and' to to a solutíon of sodium borrcl¡¡driae (1.0 g) i¡r water "f), thj.s was add.ed. a suspension of {.-nii¡p-2r2r-bipyridyl-1-oxide (0.5O g) i-n methanof (tCO ml)o the,nr:ixturæ was .'¡varrned. slightly and. left to stand' with occasional shaki:rg for 20 rninutes" Excess sod.ir:r¡ boroÏ$rd.rid-e was destroyed. rv:ith krydrochlor.ic acid., the solution fiJ.tered' and' nad'e basio, anrl then extracted wii¡h chlo¡.oform (3 * 5O nù) which on evaporation gave a dark brov¡n solido Crysta|lizaljron of this so]id. from ethanol gave d.ä¡ride-N-oxid'e, orange ye ILow ne eèles of I ilt ;¡,is lr-.( 2 r 2r -bipyridyl) mopo and. nÉxed. m.po 1!Bo. Evaporation of tlre mother liquors to d-ryness and, recrystallization of the remaining so1i.d. from petroleum et'krer, gave ,lranino-2r2t-bipyridyl (0.29 g; 75Ð as colourless needlês¡ IIIepr 129oo (Found.: cr 7o.5i Hr 5J+i Nr 2l+.1" ctOHgN, requi-:res: Q, JO'Z; Hr 5"3i

?)+"6{") N., " Aoetylation of this a¡rine with acetic acid-acetic anhydride -135-

¡Éxture (t:f ) gave þacetylami-no-.2r2t-bípyri4fl¡ wlcich was pr'rified- by orystalIi zat::on f¡ç¡¡¡ y¡ater as pale yellow need.Ies, mop. 187oo (Fol¡nd.¡ ar 67.gi Tr, J.2; Nr 19.8. cfltrNro reeui'res: c r 67.6; Hr 5.2; N, 19'T/o)'

(ii) Red.uctio4 I'rith Raney nj.ckel and. palladium/carb.on¡, - Red'uction of 4-nitro-2r21-bipyrid.yl-1-oxide with both lV-J Raney nickel a{rd lq" pallad.iuny'carbon catalysts j¡r ethanol r.¡nder one atrnosphere of ÌÐfcì.rogen at room tempera'Lure, gave similar mixtu:res of pnod.ucts, melting betrveen ßA-ZZOoC. Infrared. spectr:a of t}¡ese rnixtures showed no absorption 4 above J1O0 cm-to Fractional recrystallization from ethanol gave a coutpowrd' m"p. tg8o witfr analysis figunes conresponding closeþ to CedtLNgO' the !¡rrìrro speotnrm lCmfr) showed. on$ seven aromatic protons from 1.11+ to 2.62. The mass spectnrm shor,¡ed. a molecular ion at' ny'e 354 (.5%) ard- a

stable (U-t6) peak at r{e 338 Øg%)o Infr^ared. arvl r¡ltravioLet absorption

of this compound. and. the ¡n-ixtu¡e above were siuLifaro

(äi) Ri{uction lv-i.bln. pjrl.ladi-um/barium carbonate. - l+-Nitro-2r2r- bipyri{y1-1-oxid.e (0.50 g) , 5% palLad.iur/barir"¡m s¿rbe¡ate (O.IZ ù and' etlcanol (fOO mf) were sti:red. und.er one atmos¡ùr'ere of tgrd-rogen at 45o

for 36 hourso the solution was fiJ-tered., evaporated. to dryness, and. the ligþt brown residue crystallized. from ethanol to give pale or:ange

need.l-es (o.27 g) , m.p. 129o o -136-

the j.nfrared. speot'.uo (Cilcfr) showeô no abso4rtion above at 51CO our-1o Ultraviol,et absorption (etha¡ro}) sÏ¡owed maxl¡¡r¡m J82, absorption 368, 278, ard. ll8 rnuo The n¡mcto spectn¡n (CDC1,) shov¡ed bnoad' ard. dr¡o to two aliphatic proto¡s ad.jacent to a nitrogen atom at 6.95 7.05"

The rnass spectrun showed a molecular ion at n/e 4, @Ã) an¿ a stable

(¡¡-r) peak ai, n/e 44 Q¿+fi).

*** -137-

AFfÐNDÐ(

comporueds Nomenclature of p{åanosi-.1-icon " The nomenclature used for the organosilicon compouncls in

Chapter I j.s that recommend.ed by the ConnÉssion of Nomenclature of grganic,Ghem1stry of the ï.U.P.A.C. anC ad.opted. by the Chemical *oci.W!75 the basis for naning all of these compoirtds is the compound' sila¡¡s, (qmt).

Hyd.ro:qy d.erivafives of silane are d.enoted, by the sufYlix rr-olrr, as in silanol (UrSi-Off), and. sj.lanedj.of (ffrSi(On)r)"

compound.s with silicon*o4ygen-silicon bond.s arre te¡med (ttrSi-O-Sjlll) siJoxanes; for exaruple d.isiloxane " Any organic d.erivatives of these compounds hai¡e the no¡mal prefix in alphabetical o¡der d.enotirg these substituents. For example t i^f the four lgrd.rogens of silar¡e are replaced. by phergrl or¡-to\rl groups,

the compor-¡r¡ds ane calLed. tetraphergrlsilane and. tetra-þ-tofyf) siLa¡re respectivelyo $irnilarly, silanol, silaned.ioI, and. silo:canes are used as the basis for naniing their derivatir¡eso cyclic compor:nds have the pnefix ilcycIotr, for example hexpher¡rlcyclotrisiloxane (81)" Rad.icals are named. as d.erivatives of silyl etc.¡ e.go the tripher¡ylsiþl rad.ical PþÍii-. Ph o-JPh ,Jl I-Ph Phl I (81) 00 \i/ Ph Ph -13Þ

BEFBFtsNCESì.

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173" Rao, RoPo, Agg!,J,.1]þg"r 1961+, !2, 1.

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¡¡¡*ú

Sasse, W. H. F. & Wade, K. O. (1966), Synthetical applications of activated metal catalysts. XXV. The hydrogenolysis of some phenyl derivatives of silicon by Raney nickel. Australian Journal of Chemistry, 19(10), 1897-1908.

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